Realization of a coherent optical DPSK (differential phase-shift keying) heterodyne transmission system with 565 MBit/s at 1.064 um

摘要

We describe the realization of an optical 565Mbit/s DPSK heterodyne breadboard communication systems at 1064nm for experiments concerning future space applications. The optical transmitter is based on a diode-pumped Nd:YAG single mode TMC laser with 620mW which has been offset-locked to a stable low power ring laser. Phase modulation is obtained y a LiNbO$-3$/ travelling wave modulator. The receiver frontend consists of two InGaAs PIN photodiodes in a balanced configuration and a transimpedance amplifier. The IF of 1130 MHz is stabilized by an AFC which is able to follow frequency deviations of more than 10GHz. The DPSK encoder and the clock/data recovery unit is based on GaAs technology. The whole system works with a single 12V power supply useful when performing outdoor experiments. To obtain a bit error rate of 10$+$MIN@10$/ a received light power of less than $MIN@48Bm is required.