Investigation On Generation, Demodulation And Transmission Characteristics Of Advanced Optical Phase-shifted Modulation Formats

Higher and higher request for information transmission rate causes rapid development of optical communication system. The advanced optical modulation formats also become research hotspot recently. Supported by the Foundation of Huawei Technologies Co. Ltd.—multichannel OTDM system implementation scheme and key technology research (Grant No. YJCB2006045TR) and New Century Excellent Talents Program in Ministry of Education (Grant No. NECT-04-0715), some researches on advanced optical phase shift modulation formats are presented in this thesis. The main contents are listed as follows:(1) The research background,significance and characteristics of all kinds of optical modulation formats are clarified. Three novel schemes for generation and demodulation of optical phase shift modulation formats are proposed for the first time.(2) A novel scheme for generating a novel phase shift modulation format M-DPSK by adding a MZI after conventional modulation of DPSK is proposed. The principles of M-DPSK's modulation and demodulation are presented. The theoretical analyses of the whole process are given. Theoretical results are simulated using Optisystem software. Experimental results for 40Gb/s DPSK and M-DPSK are obtained.(3) A novel scheme for demodulating DQPSK by two Gaussian-shaped bandpass filter is proposed. Conventional demodulation scheme is given. The principle of novel demodulating DQPSK scheme is presented. The theoretical analyses of demodulation process are also carried out. The novel scheme is compared with the conventional scheme. At last a substitution scheme is supplemented.(4) A novel scheme for demodulating wavelength division multiplexing DQPSK system by AWG demultiplexer is proposed. The demodulation principle is presented. The respective property is discussed. Theoretical results are simulated using VPI software.