Research On The High Speed Tunable Optical Comb Filter And Its Control System

As special wavelength selective filters, optical comb filter have wide applications in optical fiber communication, from multi-wavelength laser sources and wavelength division multiplexing (WDM) to photoelectric measurement. In this dissertation, our research is on tunable comb filter based on transparent ferroelectric ceramic. With central wavelength and channel isolation tunable comb filters, channel shift and signal processing will be much more simple and efficient in dynamic optical networks.In this dissertation, a novel central wavelength and isolation tunable fiber-optic comb filter is proposed. Parameters of the components used in the comb filter structure are calculated and designed to get better performance. According to theoretical and quantitative analysis, the channel isolation can be improved to reach a maximum by applying a voltage to electro-optic crystal to compensate for the alignment errors.In this dissertation, we design a control system, in which the driving-voltage can be adjusted to compensate the effect of working temperature. In our control system, the detected light wave signal contains information about the change in the transient spectral transmission of filter, and controller chip is used to adjust the driving-voltage to maintain spectral transmission stable according to the light wave signal.Finally, experiments show that the proposed control system performs well. Compared with traditional comb filters, the tunable comb filter have the features of low insertion loss, large dynamic range, high tuning speed, compact, steady performance, and polarization insensitivity.