Nonlinearity-compensation-free optical frequency domain reflectometry based on electrically-controlled optical frequency sweep

摘要： A nonlinearity-compensation-free optical frequency domain reflectometry (OFDR) scheme is proposed and experimentally demonstrated based on the electrically-controlled optical frequency sweep. In the proposed scheme, the linear frequency sweep light is generated by propagating an ultra-narrow-linewidth continuous-wave light through an electro-optic frequency shifter which consists of a dual-parallel Mach-Zehnder modulator and an electronic 90° hybrid, where the electro-optic frequency shifter is driven by a linear frequency modulated signal generated by a direct digital synthesizer. Experimental results show that the spatial resolution and signal-to-noise ratio (SNR) of the proposed OFDR scheme without the nonlinear phase compensation are comparable to those of the OFDR employing a commercial tunable light source (TLS), an auxiliary interferometer and a software-based nonlinear phase compensation method. The proposed OFDR scheme is helpful to reduce the complexity of optical structure and eliminate the difficulty of developing nonlinear phase compensation algorithm.