Apparatus for extracting an optical clock and apparatus for demultiplexing a time-division multiplexed signal

Claim 1

An apparatus for extracting an optical clock, comprising: a voltage controlled oscillator (VCO) for generating a clock signal of a frequency dependent on an applied voltage; a clock light generator coupled to said VCO for generating a clock light of an intensity modulated light which is synchronous with said clock signal; an optical coupler for combining a pulse coded signal light and said clock light; a non-linear optical medium for generating a third order non-linear optical effect by receiving said signal and clock lights combined in said optical coupler; an optical extractor for extracting at least one light from outputs lights of said non-linear optical medium; and a control circuit for applying a control voltage dependent on said one light to said VCO, wherein said control circuit supplies said VCO with said control voltage which is dependent on a time-mean value in power of said one light, to cause said VCO to generate said clock signal and said clock light generator to generate said clock light, said clock signal and said clock light being locked in phase to said signal light and having a clock frequency of one Nth or N times of a clock frequency of said signal light, where N is an integer, and said output lights being said signal light, said clock light, and four-wave mixing lights generated by said signal and clock lights.

Claim 2

An apparatus for extracting an optical clock, comprising: a voltage controlled oscillator (VCO) for generating a clock signal of a frequency dependent on an applied voltage; a clock light generator coupled to said VCO for generating a clock light of an intensity modulated light which is synchronous with said clock signal; an optical coupler for combining a pulse coded signal light and said clock light; a non-linear optical medium for generating a third order non-linear optical effect by receiving said signal and clock lights combined in said optical coupler; an optical extractor for extracting at least one light from outputs lights of said non-linear optical medium; and a control circuit for applying a control voltage dependent on said one light to said VCO, wherein said control circuit supplies said VCO with said control voltage which is dependent on a time-mean value in power of said one light, to cause said VCO to generate said clock signal and said clock light generator to generate said clock light, said clock signal and said clock light being locked in phase to said signal light and having a clock frequency of one Nth or N times of a clock frequency of said signal light, where N is an integer, and said output lights being said signal light, said clock light, and four-wave mixing lights generated by said signal and clock lights.

Claim 6

An apparatus for demultiplexing a time-division multiplexed signal, comprising: a voltage controlled oscillator (VCO) for generating a clock signal of a frequency dependent on an applied voltage; a clock light generator coupled to said VCO for generating a clock light of an intensity modulated light which is synchronous with said clock signal; an optical coupler for combining a pulse coded signal light and said clock light, said signal light comprising N-time division sequential lights; a non-linear optical medium for generating a third order non-linear optical effect by receiving said signal and clock lights combined in said optical coupler; an optical extractor for extracting at least one light from outputs lights of said non-linear optical medium; a control circuit for applying a control voltage dependent on said one light to said VCO; and an optical divider for dividing said one light into first and second lights, and first light being a demultiplexed light having a clock frequency of one Nth of a clock frequency of said signal light, and said second light being supplied to said control circuit, wherein said control circuit supplies said VCO with said control voltage which is dependent on a time-mean value in power of said second light to cause said VCO to generate said clock signal and said light generator to generate said clock light, said clock signal and said clock light being locked in phase to said signal light, and said output lights being said signal light, said clock light, and four-wave mixing lights generated by said signal and clock lights.

Claim 7

An apparatus for demultiplexing a time-division multiplexed signal, comprising: a voltage controlled oscillator (VCO) for generating a clock signal of a frequency dependent on an applied voltage; a clock light generator coupled to said VCO for generating a clock light of an intensity modulated light which is synchronous with said clock signal; an optical coupler for combining a pulse coded signal light and said clock light, said signal light comprising N-time division sequential lights; a non-linear optical medium for generating a third order non-linear optical effect by receiving said signal and clock lights combined in said optical coupler; an optical extractor for extracting at least one light from outputs lights of said non-linear optical medium; a control circuit for applying a control voltage dependent on said one light to said VCO; and an optical divider for dividing said one light into first and second lights, and first light being a demultiplexed light having a clock frequency of one Nth of a clock frequency of said signal light, and said second light being supplied to said control circuit, wherein said control circuit supplies said VCO with said control voltage which is dependent on a time-mean value in power of said second light to cause said VCO to generate said clock signal and said light generator to generate said clock light, said clock signal and said clock light being locked in phase to said signal light, and said output lights being said signal light, said clock light, and four-wave mixing lights generated by said signal and clock lights.

Claim 8

An apparatus for demultiplexing a time-division multiplexed signal, comprising: a voltage controlled oscillator (VCO) for generating a clock signal of a frequency dependent on an applied voltage; a clock light generator coupled to said VCO for generating a clock light of an intensity modulated light which is synchronous with said clock signal; an optical coupler for combining a pulse coded signal light comprising N time-division sequential lights and said clock light corresponding in timing to one of said N time-division sequential lights; a non-linear optical medium for resulting in a phase shift or a frequency shift on said one of said N time-division sequential lights and generating four-wave mixing lights by receiving said signal and clock lights combined in said optical coupler; an optical extractor for extracting one light from said signal and clock lights and said four-wave mixing lights; a control circuit for applying a control voltage dependent on said one light to said VCO; and an optical demultiplexer for demultiplexing said signal light from said non-linear optical medium to separate a switched signal light of said one of N time-division sequential lights and a non-switched signal light of remaining lights of said N time-division sequential lights; wherein said control circuit supplies said VCO with said control voltage which is dependent on a time-mean value in power of said one light to cause said VCO to generate said clock signal, and said clock light generator to generate said clock light, said clock signal and said clock light being locked in phase to said signal light.

Claim 9

An apparatus for demultiplexing a time-division multiplexed signal, comprising: a voltage controlled oscillator (VCO) for generating a clock signal of a frequency dependent on an applied voltage; a clock light generator coupled to said VCO for generating a clock light of an intensity modulated light which is synchronous with said clock signal; an optical coupler for combining a pulse coded signal light comprising N time-division sequential lights and said clock light corresponding in timing to one of said N time-division sequential lights; a non-linear optical medium for resulting in a phase shift or a frequency shift on said one of said N time-division sequential lights and generating four-wave mixing lights by receiving said signal and clock lights combined in said optical coupler; an optical extractor for extracting one light from said signal and clock lights and said four-wave mixing lights; a control circuit for applying a control voltage dependent on said one light to said VCO; and an optical demultiplexer for demultiplexing said signal light from said non-linear optical medium to separate a switched signal light of said one of N time-division sequential lights and a non-switched signal light of remaining lights of said N time-division sequential lights; wherein said control circuit supplies said VCO with said control voltage which is dependent on a time-mean value in power of said one light to cause said VCO to generate said clock signal, and said clock light generator to generate said clock light, said clock signal and said clock light being locked in phase to said signal light.