The Development Of100Gbit/s DP-QPSK Integrated Coherent Optical Receiver Based On Planar Lightwave Circuit

Recently, in order to meet the continuous growth in demand for bandwidth of theoptical transport network,100Gbit/s coherent optical communication system based on dualpolarization quadrature phase-shift keying (DP-QPSK) modulation format has been paidimportant attention.100Gbit/s coherent receiver is a key component of100Gbit/s coherentoptical communication system for demodulating DP-QPSK signals and the research on thecoherent receiver has great economic value and wide range of application propects. Thisthesis spreads out the discussions around the design and measurement of optical90°hybrid,the technology of hybrid integration between planar lightwave circuit (PLC) and PD, andthe performance evaluation of coherent receiver. The main work and innovation points areas follows:(1) An optical90°hybrid based on the materials of silicon on silica is systematicallyresearched, included the theoretical analysis, design and optimize, tolerance analysis andtest. After fabrication and optical coupling, the test results indicate that the wavelengthdependent loss is less than0.3dB, polarization dependent loss is less than0.5dB. At thesame time, the output phase error is measured-3.5°maximun by two methods of delay lineand frequency shifter. All the indicators are better than the requirements of OIF standard.(2) A technology of hybrid integration between90°optical hybrid and high speed PDarray is proposed, including the design of a compact hybrid integrated structure and apassive alignment method through monitoring the position of the image. Through finiteelement analysis of the hybrid integrated structure and temperature experimental test, bothresults demonstrate that the coherent receiver developed by this project has hightemperature stability and in the range of-5to80℃,the variation of PDs’ responsivity isless than±0.2dB and coincides with the less than0.5dB variation in coherent receiver.(3) The method of testing the performance of coherent receiver has been explored,including S-parameter, common mode rejection ratio (CMRR), harmonic distortion (THD),phase and skew error. A platform is built for testing and results show that3dB bandwidth can be achieved by20GHz, CMRR can be achieved by-20dB at a frequency of25GHz,THD0.13%, and all the indicators meet the requirements of OIF standard. Through back toback measurement in100Gbit/s coherent optical communication system, coherent receiverhas a good demodulation of DP-QPSK signals and achieves an OSNR of13.08dB atmaximum correctable error rate.