Phase lock loop circuit using optical correlation detection

Claim 2

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling the phase of said first oscillating means by comparing the phase of said electrical signal outputted from said optical receiving means and the phase of said signal produced by multiplying the repetition frequency by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; traveling-wave semiconductor laser amplifying means for amplifying a signal produced by said combination; and optical splitting means for extracting from an optical output signal of said traveling-wave semiconductor laser amplifying means only the wavelength of said optical output signal which is a correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set to values such that said signals coherently interfere with each other.

Claim 3

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling the phase of said oscillating means by comparing the phase of said electrical signal outputted from said optical receiving means and the phase of said signal produced by multiplying the repetition frequency signal by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; optical fiber for generating four-wave mixing of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said optical fiber only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set in the vicinity of a zero dispersion wavelength of said optical fiber.

Claim 4

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling the phase of said oscillating means by comparing the phase of said electrical signal outputted from said optical receiving means and the phase of said signal produced by multiplying the repetition frequency signal by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; optical fiber for generating four-wave mixing of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said optical fiber only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set in the vicinity of a zero dispersion wavelength of said optical fiber.

Claim 5

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said oscillating means by comparing a phase of said electrical signal outputted from said optical receiving means and a phase of said signal produced by multiplying the repetition frequency signal by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; nonlinear optical crystal for generating a sum-frequency light of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said nonlinear optical crystal only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 6

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said oscillating means by comparing a phase of said electrical signal outputted from said optical receiving means and a phase of said signal produced by multiplying the repetition frequency signal by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; nonlinear optical crystal for generating a sum-frequency light of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said nonlinear optical crystal only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 7

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of said electrical signal outputted from said optical receiving means and a phase of said signal produced by multiplying the repetition frequency by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from an optical fiber loop constructed by means of an optically coupling means for inputting said optical signal pulse, means for inputting said optical clock pulse, and an optical fiber; and optical splitting means for extracting from an optical output signal of said optical fiber loop only the wavelength of said optical signal; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 8

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of said electrical signal outputted from said optical receiving means and a phase of said signal produced by multiplying the repetition frequency by n, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from an optical fiber loop constructed by means of an optically coupling means for inputting said optical signal pulse, means for inputting said optical clock pulse, and an optical fiber; and optical splitting means for extracting from an optical output signal of said optical fiber loop only the wavelength of said optical signal; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 9

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating a sum, difference, or sum and difference of output signal frequencies of said first oscillating means and said second oscillating means; optical pulse generating means driven by means of an output signal of said frequency mixing means for generating an optical pulse possessing a sufficiently narrow pulse width for including nth harmonics, n being a natural number, component; optical correlation detecting means for outputting said correlation component of said optical signal pulse and said optical clock pulse; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said oscillating means by comparing a phase of said output signal of said optical receiving means and a phase of said signal produced by multiplying the frequency of said a.c. signal by n, such that said phase difference of said signals results in a predetermined value; wherein, said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 10

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating a sum, difference, or sum and difference of output signal frequencies of said first oscillating means and said second oscillating means; optical pulse generating means driven by means of an output signal of said frequency mixing means for generating an optical pulse possessing a sufficiently narrow pulse width for including nth harmonics, n being a natural number, component; optical correlation detecting means for outputting said correlation component of said optical signal pulse and said optical clock pulse; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said oscillating means by comparing a phase of said output signal of said optical receiving means and a phase of said signal produced by multiplying the frequency of said a.c. signal by n, such that said phase difference of said signals results in a predetermined value; wherein, said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 11

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; traveling-wave semiconductor laser amplifying means for amplifying a signal produced by said combination; and optical splitting means for extracting from an optical output signal of said traveling-wave semiconductor laser amplifying means only the wavelength of said optical output signal which is a correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set to values such that said signals coherently interfere with each other.

Claim 12

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; traveling-wave semiconductor laser amplifying means for amplifying a signal produced by said combination; and optical splitting means for extracting from an optical output signal of said traveling-wave semiconductor laser amplifying means only the wavelength of said optical output signal which is a correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set to values such that said signals coherently interfere with each other.

Claim 13

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling the phase of said first oscillating means by comparing the phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and the phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; traveling-wave semiconductor laser amplifying means for amplifying a signal produced by said combination; and optical splitting means for extracting from an optical output signal of said traveling-wave semiconductor laser amplifying means only the wavelength of said optical output signal which is a correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set to values such that said signals coherently interfere with each other.

Claim 14

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling the phase of said first oscillating means by comparing the phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and the phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; traveling-wave semiconductor laser amplifying means for amplifying a signal produced by said combination; and optical splitting means for extracting from an optical output signal of said traveling-wave semiconductor laser amplifying means only the wavelength of said optical output signal which is a correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set to values such that said signals coherently interfere with each other.

Claim 15

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; optical fiber for generating four-wave mixing of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said optical fiber only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set in the vicinity of a zero dispersion wavelength of said optical fiber.

Claim 16

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; optical fiber for generating four-wave mixing of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said optical fiber only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set in the vicinity of a zero dispersion wavelength of said optical fiber.

Claim 17

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; optical fiber for generating four-wave mixing of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said optical fiber only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set in the vicinity of a zero dispersion wavelength of said optical fiber.

Claim 18

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; optical fiber for generating four-wave mixing of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said optical fiber only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse, and said wavelengths of said optical signal and optical output of said optical pulse generating means are set in the vicinity of a zero dispersion wavelength of said optical fiber.

Claim 19

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; nonlinear optical crystal for generating a sum-frequency light of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said nonlinear optical crystal only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 20

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; nonlinear optical crystal for generating a sum-frequency light of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said nonlinear optical crystal only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 21

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; nonlinear optical crystal for generating a sum-frequency light of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said nonlinear optical crystal only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 22

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from a optical combining means for combining said optical signal pulse and said optical clock pulse; nonlinear optical crystal for generating a sum-frequency light of said optical signal pulse and said optical clock pulse; and optical splitting means for extracting from an optical output signal of said nonlinear optical crystal only the wavelength of said correlation component of said optical signal pulse and said optical clock pulse; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 23

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from an optical fiber loop constructed by means of optically coupling a means for inputting said optical signal pulse, means for inputting said optical clock pulse, and an optical fiber; and optical splitting means for extracting from an optical output signal of said optical fiber loop only the wavelength of said optical signal; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 24

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from an optical fiber loop constructed by means of optically coupling a means for inputting said optical signal pulse, means for inputting said optical clock pulse, and an optical fiber; and optical splitting means for extracting from an optical output signal of said optical fiber loop only the wavelength of said optical signal; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 25

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from an optical fiber loop constructed by means of optically coupling a means for inputting said optical signal pulse, means for inputting said optical clock pulse, and an optical fiber; and optical splitting means for extracting from an optical output signal of said optical fiber loop only the wavelength of optical signal; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 26

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating, by means of mixing an output signal of said first oscillating means and an output signal of said second oscillating means, a signal of a frequency corresponding to a sum, difference, or sum and difference of frequencies of said output signals; optical pulse generating means for generating an optical pulse of a repetition frequency equal to the frequency of an output signal of said frequency mixing means; optical multiplexing means for conducting optical time-division-multiplexing of said optical pulse, and for multiplying said repetition frequency by n, n being a natural number; optical correlation detecting means for outputting the product of light intensities of an optical signal pulse and an optical clock pulse outputted from said optical multiplexing means; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said optical correlation detecting means is formed from an optical fiber loop constructed by means of optically coupling a means for inputting said optical signal pulse, means for inputting said optical clock pulse, and an optical fiber; and optical splitting means for extracting from an optical output signal of said optical fiber loop only the wavelength of optical signal; said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 27

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating a sum, difference, or sum and difference of output signal frequencies of said first oscillating means and said second oscillating means; optical pulse generating means driven by means of an output signal of said frequency mixing means for generating an optical pulse possessing a sufficiently narrow pulse width for including nth harmonics, n being a natural number, component; optical correlation detecting means for outputting said correlation component of said optical signal pulse and said optical clock pulse; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 28

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating a sum, difference, or sum and difference of output signal frequencies of said first oscillating means and said second oscillating means; optical pulse generating means driven by means of an output signal of said frequency mixing means for generating an optical pulse possessing a sufficiently narrow pulse width for including nth harmonics, n being a natural number, component; optical correlation detecting means for outputting said correlation component of said optical signal pulse and said optical clock pulse; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by 1/n, and a phase of said a.c. signal, such that said phase difference of said signals results in a predetermined value; wherein, said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 29

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating a sum, difference, or sum and difference of output signal frequencies of said first oscillating means and said second oscillating means; optical pulse generating means driven by means of an output signal of said frequency mixing means for generating an optical pulse possessing a sufficiently narrow pulse width for including nth harmonics, n being a natural number, component; optical correlation detecting means for outputting said correlation component of said optical signal pulse and said optical clock pulse; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.

Claim 30

Optical clock phase lock loop comprising: first oscillating means in which an oscillation frequency and phase vary according to exterior control; second oscillating means for outputting an a.c. signal; frequency mixing means for generating a sum, difference, or sum and difference of output signal frequencies of said first oscillating means and said second oscillating means; optical pulse generating means driven by means of an output signal of said frequency mixing means for generating an optical pulse possessing a sufficiently narrow pulse width for including nth harmonics, n being a natural number, component; optical correlation detecting means for outputting said correlation component of said optical signal pulse and said optical clock pulse; optical receiving means for converting an optical output of said optical correlation detecting means into an electrical signal; and means for controlling a phase of said first oscillating means by comparing a phase of a signal produced by multiplying said frequency of said electrical signal outputted from said optical receiving means by m/n (m is a rational number), and a phase of a signal produced by multiplying the frequency of said a.c. signal by m, such that said phase difference of said signals results in a predetermined value; wherein, said oscillation frequency of said first oscillating means is set to 1/n of the bit rate of said optical signal pulse.