DISPERSION COMPENSATING METHOD AND TRANSMITTING DEVICE FOR LIGHT PULSE

摘要

PROBLEM TO BE SOLVED: To reduce tertiary dispersion, to increase the degree of freedom of design, and to facilitate handling by extending the time base of light pulse and imposing phase modulation on extended pulses having extended pulse width with a sine wave, and compressing the time base of the extended light pulses whose phases have been shifted and obtaining the light pulses having the original pulse width. SOLUTION: On the transmission line for guiding light pulses 12a received from a light pulse generation source 11 to an optical phase modulator 14, the guided light pulses 12a are imported with secondary dispersion represented as the product of length L1 and a secondary dispersion coefficient β2-1. Through this secondary dispersion, the light pluses 12a are extended in the time base and guided as the extended pulses 12b to the optical phase modulator 14. The extended pulses 12b propagated in a 2nd optical fiber 14b are compressed in the time base by being given reverse dispersion represented as the product of the length L2 and secondary dispersion coefficient β2-2. The optical phase modulator 14 imposes phase modulation on the extended pulses 12b by using part of the waveform of a sine wave electric signal 14a to compensate the tertiary dispersion of the whole transmission line 13.