Broadband tunable single-mode single-polarization fiber

Traditional single-mode single-polarization (SMSP) fibers are very difficult to produce and their working bandwidths are narrow. So a broadband tunable SMSP fiber device in this paper is designed. Using refractive index-matching coupling method, the fiber can achieve SMSP transmission from 1.25 μm to 1.6 μm. The adjusting range is about 350 nm. It is worth noting that its working wavelength covers 1310 nm and 1550 nm, which are two important communication windows. In addition, by adjusting the refractive index of the fillers, the device can realize the unique switch function, which has great significance for the establishment and application of optical fiber network.