基于失配光纤耦合器的波长特性，从理论上详细分析了两芯间隔d，两芯之间的失配度Δβ及耦合区长度z对其光谱特性的影响。结果表明，当Δβ和d较小时光纤耦合器可以成为梳状滤波器。Δβ主要影响梳状滤波器的消光比，z和d在两芯子匹配的情况下主要影响峰值波长位置和间隔。通过将一根两芯间隔d=12 μm的单模双芯光纤(TCF)的一个芯子熔接在两根单模光纤(SMF)之间，实验制得基于双芯光纤耦合器的全光纤型梳状滤波器，其消光比可达25 dB，插入损耗为3.1 dB。通过使用不同长度的TCF获得了不同的峰值波长间隔，并使用波长为248 nm的紫外光对其峰值波长和消光比进行了调节。

Based on the wavelength characteristic of mismatch fiber coupler, the effects of the distance d and the mismatch Δβ between the two cores, the coupling length z on its spectrum characteristics are analyzed theoretically. It is proposed that the fiber coupler can be a comb-filter when Δβ and d are very small. Δβ mainly effects the extinction ratio, d and z mainly effect the interval of the resonant peaks respectively when the two cores are matched. An all-fiber comb-filter based on twin-corn fiber coupler is experimentally fabricated by splicing a section of single mode twin-core fiber (TCF) with core center-to-center distance of 12 μm between two single mode fibers (SMFs), and the filter′s extinction ratio and insertion loss are 25 dB and 3.1 dB respectively. The interval of the resonant peaks can be changed by using TCF of different lengths, and the peak wavelength and extinction ratio are modulated by ultraviolet light of 248 nm.