Study Of Performance Monitoring Technology In Optical Modulation Signal Generation And Transmission

Optical fiber communication network is an important component of moderncommunications network, the huge capacity and high rate demand of optical fibercommunication network could not fully meet only by physical improvement of thestandard optical fibe. In order to converge traditional optical network to futureoptical network which meet the needs of transition traffic, numerous technology andnetwork architecture concepts for generating optical signal modulation flexibilityhave been proposed.In this dissertation, the basic structure of optical communication systems arebriefly reviewed. Elicit high order modulation formats and coherent detectiontechnology from conventional intensity modulation/direct detection, brieflyintroduces the basic principles of higher order modulation and related theories andformulas, methods and formulas of coherent detection. Several key steps of digitalsignal processing of coherent detection are summarized. The main parameters ofnetwork performance monitoring and basic monitoring means are described, theimportance of controlling of phase modulator and the limitations of conventionalmethod for calculating the error vector magnitude comprises the case of the opticalintersymbol interference noise ratio and bit error rate estimates.This dissertation presents a way of using asynchronous sampling to build ahistogram for cascaded phase modulator drive signal amplitude with automaticfeedback control methods. Compared to dither control signal modulator, dither-freecontrol signal is more stable. The independence irrational insensitive characteristicof controls reduces the difficulty of the control module. The fact of the transmissionlink length, channel environment, the rate of capacity requirements are not the samein the complex optical network, a time-hybrid optical modulator transmitter conceptis proposed. The software configuration of the transmitter controlled by the five dataport, various time-domain modulation symbols hybrid transmission, improving thespectral efficiency of the network bandwidth.For monitoring the performance of the optical network signal, this paperpresents a method of the error vector magnitude that contains tight optical filterscenario. With the increase of different kinds and numbers of optical devices, opticalnetworks become more diverse and complex, and the resulting filter cumulativeeffect makes the inter-symbol interference is also increasing, traditional error vectormagnitude algorithm does not consider the impact of inter-symbol interferencewhich can not accurately estimate optical signal to noise ratio and bit error rate. Byconsidering the before and after symbols of the target symbol, the calculations of error vector magnitude of the proposed algorithm can accurately estimate the opticalsignal to noise ratio with the situation under tight optical filter. The estimationaccuracy of bit error rate can be improved by optimizing inter-symbol interferenceerror vector.