Optical transmitting apparatus for minimal dispersion along an optical fiber

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.

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.