Measurement of Residual Intensity Modulation of Y Waveguide Modulator

To facilitate the analysis of mechanism of the residual intensity modulation of Y waveguide modulator and improve the measurement speed, a method for testing the residual intensity modulation of Y waveguide modulator was put forward. The system uses Spartan-6 series FPGA as the master control chip, to control analog-to-digital conversion chip ADS5560 to collect optical modulation signals after the photoelectric conversion, sending the collected data package to PC through UART communication mode, gaining the size of the residual intensity modulation and waveform information of Y waveguide modulator. According to the size of residual intensity modulation and waveform information, the linear output caused by mode field change was analyzed and interference output caused by stray light and the light interference mechanism was also analyzed. The experiments show that the system stability is good, having important significance for the development of Y waveguide modulator.