Study On The Bidirectonal Transmission System Of DQPSK Signals Using Wavelength Shfiting

Since the21st century, human society’s demand for communication is increasingall the time, and the explosive growth of information on optical fiber communicationsystem is becoming more and more demanding, How to make smooth transition to100G communication network is an important topic of the optical fibercommunication system expansion. Using Bi-directional transmission technology canmake the fiber utilization double, so as to maximize the use of existing bandwidthresources without laying a new optical fiber. It is considered to be a feasible schemeof expanding capacity of optical fiber communication systems.This paper mainly studies the transmission performance of Bi-directionaltransmission system. First, the basic theories of the DQPSK digital transmissionsystem and the optical fiber communication system are discussed, and the keytechnologies such as Rayleigh backscattering and the special effect of SRS and SBSof the Bi-directional transmission system are analyzed. Secondly combined with theresults of the three parts to build the Bi-directional Transmission system of DQPSKSignals in the Optisystem7.0platform. Then the method of comparative analysis hascarried on the different duty ratio of RZ-DQPSK and CSRZ-DQPSK system contrast,the contrast between the traditional unidirectional transmission system andBidirectional transmission system, and we explores Bidirectional transmissionsystem by changing different parameters to study the optimal transmission power andthe maximum transmission distance. Finally we analyzes the influence of channelinterval and channel number on its transmission characteristics. Results show that inthe condition of3dbm transmission power,8channels,200GHZ channel spacingusing the duty ratio of33%RZ-DQPSK signals, the Bi-directional transmissionsystem has the best performance, the maximum transmission distance can reach1600km or so, at the same time compared with traditional unidirectional transmissionsystem in the same condition, its Q value can increase nearly doubled.