OPTICAL RECEIVER AND OPTICAL ADD/DROP DEVICE

摘要

PROBLEM TO BE SOLVED: To eliminate the necessity of a dispersion compensation fiber for a receiving terminal station. SOLUTION: Signal light (wavelength λs) inputted from an optical transmission line to an input terminal 10 is made incident upon a multiplexer 14 through an optical amplifier 12. The multiplexer 14 multiplies output light from the amplifier 12 by probe light (wavelength λp) from a probe light source 16 and applies the multiplexed light to an EA modulator 18. The modulator 18 superposes the waveform of the signal light of the wavelength λs on the probe light. An optical BPF 20 transmits only the component of probe wavelength λp out of output light from the modulator 18. A light receiving element 22 converts the output light of the BPF 20 into an electric signal and an amplifier 24 electrically amplifies the output of the element 22. An BPF 26 extracts the clock component of input signal light from the output of the amplifier 24 and supplies the extracted component to a driving circuit 28. The circuit 28 pulse-drives the probe light source 16 at the same frequency as that of the clock signal outputted from the BPF 26 and adjusts the phase of the pulse so as to synchronize it with a current pulse generated from the modulator 18. A laser light source 16 generates a probe light pulse in accordance with a driving signal outputted from the circuit 28.