US5184243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical transmitting apparatus for minimal dispersion along an optical fiber
Assignee: NEC Corp
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Filing: 1990-11-30
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Granted: 1993-02-02
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Expires: 2010-11-30
Abstract
Abstract A plurality of transmitting signal lights are supplied from a semiconductor laser light source which is modulated by a current having adjusted amplitude and phase injected thereinto in an optical transmitting apparatus. The signal lights are modulated in intensity by a plurality of external modulators, and a time-difference is applied among the signal lights. Thus, the signal lights are combined to provide a transmitting signal light which is propagated through a transmission line. At this time, a frequency component having a low transmission speed is supplied to the transmission line earlier than a frequency component having a fast transmission speed in compliance with a wavelength dispersion property of the transmission line.
Inventors
- 👤 Naoya Henmi
- 👤 Tetsuyuki Suzaki
- 👤 Tomoki Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:35
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/50; H04B10/516; H04B10/532; H04B10/501; H04B10/503; H04B10/505; H04B10/5053; H04B10/54; H04B10/541; H04B10/548
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
257 words
An optical transmitting apparatus, comprising: a semiconductor laser light source for emitting a frequency-modulated light; a source of injection current; a clock signal source for generating a clock signal for modulating said injection current; means for applying said injection current to said semiconductor laser light source for modulating said emitted light in accordance with said injection current; means for adjusting an amplitude and a phase of said clock signal to modify the modulation of said injection current; n transmitting signal sources for generating n transmitting signals synchronous with said clock signal, where n is a positive integer; means for dividing said frequency-modulated light into n signal lights propagated through n light paths; n external modulators coupled to said light paths and responsive, respectively, to one of said transmitting signals, for modulating in intensity said n divided signal lights to provide n intensity-modulated lights traveling in respective ones of said n light paths; means for providing a time difference among said n intensity-modulated lights; and means for combining said n intensity-modulated lights traveling through said light paths; wherein said adjusting means adjusts said amplitude and said phase of said clock signal, so that said n intensity-modulated lights are supplied to said light paths in a time-order of frequency components having slow to fast transmission speeds in compliance with a wavelength dispersion property of said light paths; and said providing means being provided at position selected from positions between said dividing means and a corresponding one of said external modulators and between said corresponding one and said combining means.
Claim 2
Dependent Claim
257 words
An optical transmitting apparatus, comprising: a semiconductor laser light source for emitting a frequency-modulated light; a source of injection current; a clock signal source for generating a clock signal for modulating said injection current; means for applying said injection current to said semiconductor laser light source for modulating said emitted light in accordance with said injection current; means for adjusting an amplitude and a phase of said clock signal to modify the modulation of said injection current; n transmitting signal sources for generating n transmitting signals synchronous with said clock signal, where n is a positive integer; means for dividing said frequency-modulated light into n signal lights propagated through n light paths; n external modulators coupled to said light paths and responsive, respectively, to one of said transmitting signals, for modulating in intensity said n divided signal lights to provide n intensity-modulated lights traveling in respective ones of said n light paths; means for providing a time difference among said n intensity-modulated lights; and means for combining said n intensity-modulated lights traveling through said light paths; wherein said adjusting means adjusts said amplitude and said phase of said clock signal, so that said n intensity-modulated lights are supplied to said light paths in a time-order of frequency components having slow to fast transmission speeds in compliance with a wavelength dispersion property of said light paths; and said providing means being provided at position selected from positions between said dividing means and a corresponding one of said external modulators and between said corresponding one and said combining means.
Claim 3
Dependent Claim
23 words
An optical transmitting apparatus, according to claim 1, wherein: said providing means is an optical fiber having a length corresponding to said time-difference.
Claim 4
Dependent Claim
20 words
An optical transmitting apparatus, according to claim 1, wherein n is two; and said combining means is a polarized multiplexer.
Claim 5
Dependent Claim
228 words
An optical transmitting apparatus, comprising: n semiconductor laser light sources for emitting n frequency-modulated lights to travel through n light paths, where n is a positive integer; n sources of injection current; a clock signal source for generating a clock signal for modulating said sources of injection current; means for applying said injection current to said semiconductor laser light source for modulating said emitted light in accordance with said injection currents; n means for adjusting an amplitude and a phase of said clock signal to provide n modulation signals for modulating said injected currents; n transmitting signal sources for generating n transmitting signals synchronous with said clock signal; n external modulators coupled to said light paths and responsive, respectively, to one of said transmitting signals, for modulating in intensity said n frequency-modulated lights to provide n intensity-modulated lights traveling in respective ones of said n light paths; and means for combining said n intensity-modulated lights traveling through said light paths to be propagated through a transmission line; wherein said n adjusting means adjust said amplitude and said phase of said clock signal, so that a time difference is introduced among said n intensity-modulated lights, and wherein said intensity-modulated lights are supplied to said transmission line in a time-order of frequency components having slow to fast transmission speeds in compliance with a wavelength dispersion property of said transmission line.
Claim 6
Dependent Claim
228 words
An optical transmitting apparatus, comprising: n semiconductor laser light sources for emitting n frequency-modulated lights to travel through n light paths, where n is a positive integer; n sources of injection current; a clock signal source for generating a clock signal for modulating said sources of injection current; means for applying said injection current to said semiconductor laser light source for modulating said emitted light in accordance with said injection currents; n means for adjusting an amplitude and a phase of said clock signal to provide n modulation signals for modulating said injected currents; n transmitting signal sources for generating n transmitting signals synchronous with said clock signal; n external modulators coupled to said light paths and responsive, respectively, to one of said transmitting signals, for modulating in intensity said n frequency-modulated lights to provide n intensity-modulated lights traveling in respective ones of said n light paths; and means for combining said n intensity-modulated lights traveling through said light paths to be propagated through a transmission line; wherein said n adjusting means adjust said amplitude and said phase of said clock signal, so that a time difference is introduced among said n intensity-modulated lights, and wherein said intensity-modulated lights are supplied to said transmission line in a time-order of frequency components having slow to fast transmission speeds in compliance with a wavelength dispersion property of said transmission line.
Claim 7
Dependent Claim
20 words
An optical transmitting apparatus, according to claim 4, wherein n is two; and said combining means is a polarized multiplexer.
Claim 8
Dependent Claim
186 words
An optical transmitting apparatus, comprising: a semiconductor laser light source for emitting a frequency-modulated light; a source of injection current; means for applying said injection current to said semiconductor laser light source for modulating said emitted light in accordance with said injection current; an external modulator for modulating said frequency-modulated light to produce an intensity-modulated transmitting signal light responsive to a transmitting signal; a clock signal source for generating a clock signal having a frequency of n times that of said transmitting signal, said clock signal modulating said injected current, where n is an integer; and means for adjusting an amplitude and a phase of said clock signal; wherein said adjusting means adjusts said amplitude and said phase of aid clock signal to adjust a frequency shift amount and a phase of said frequency-modulated light, so that an undesirable phase-modulation component induced in said intensity-modulation of said eternal modulator is compensated, and said intensity-modulated transmitting signal light is supplied to a transmission line in a time-order of frequency components having slow to fast transmission speeds in compliance with a wavelength dispersion property of said transmission line.
Claim 9
Dependent Claim
186 words
An optical transmitting apparatus, comprising: a semiconductor laser light source for emitting a frequency-modulated light; a source of injection current; means for applying said injection current to said semiconductor laser light source for modulating said emitted light in accordance with said injection current; an external modulator for modulating said frequency-modulated light to produce an intensity-modulated transmitting signal light responsive to a transmitting signal; a clock signal source for generating a clock signal having a frequency of n times that of said transmitting signal, said clock signal modulating said injected current, where n is an integer; and means for adjusting an amplitude and a phase of said clock signal; wherein said adjusting means adjusts said amplitude and said phase of aid clock signal to adjust a frequency shift amount and a phase of said frequency-modulated light, so that an undesirable phase-modulation component induced in said intensity-modulation of said eternal modulator is compensated, and said intensity-modulated transmitting signal light is supplied to a transmission line in a time-order of frequency components having slow to fast transmission speeds in compliance with a wavelength dispersion property of said transmission line.
References Cited (Backward Citations)
US4933929A
Cited
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