Research Of Relative Phase Measurement Of Periodical Signal Based On Ultra-high Resolution Optical Spectrum

Various multiplexing method and advanced modulation formats have been used in optical fiber communication system, in order to achieve ultra-high speed, ultra-large capacity and ultra-long haul optical transmission. Therefore,analyzing the optical signal both in intensity and phase from time-domain or frequency-domain is significant. While the signal transmission rate is increasing, analyzing from time-domain is getting more difficult because of the bottleneck effect on electronic device response. As a result, this dissertation mainly focuses on methods for measuring relative phase of periodical signal based on ultra-high resolution optical spectrum analysis from frequency-domain. The main contents of the whole dissertation are as following:(1) The method of relative phase measurement of periodical signal based on ultra-high resolution optical spectrum stimulated Brillouin scattering(SBS) has been designed. By pumping stimulated Brillouin scattering(SBS) at different frequency simultaneously, a dual-channel active optical filter(AOF) is created to get relative phase of periodical signal by wavelength scanning.(2) An experimental demonstration of possibility on measuring relative phase by dual-channel active optical filter based on SBS has been realized. The amplitude- frequency response and phase-frequency response of the dual-channel AOF are measured under the condition of different input power and pump power.(3) A phase measuring system have been built relying on VPI Transmission Maker software, and the average phase errors are calculated by analyzing the parameters such as the gain of dual-channel AOF,-3d B bandwidth, frequency space and so on.(4) An experimental device for ultra-high resolution optical spectrum analysis based on SBS has been realized. The phase distribution of the NRZ-OOK signal at 1.5Gbit/s is extracted from the optical spectrum. Power and phase of each spectral component are measured. The time-domain waveform of the signal under test is obtained by inverse Fourier transform.