Compact Broadband Wavelength Selective Switch Based on in-Fiber Diffraction Device

In this study, a compact and broadband wavelength selective switch (WSS) based on a radiated tiled fiber grating with 45° tilt angle (RTFG) is proposed and experimentally demonstrated. The 45° RTFG is employed as both radiating and receiving light, replacing the fiber arrays and bulky dispersion element in the traditional WSS system. We have theoretically and experimentally investigated the proposed WSS in terms of operating wavelength range, spectral resolution and insertion loss. In the experiment, a 1 × 2 compact WSS based on 45° RTFG and LCoS is achieved, which has a wide operation range between 1520 nm and 1597 nm, covering the C+L bandwidth. The measured spectral resolution and tuning accuracy are 0.4 nm and 0.08 nm, respectively. The insertion loss of the WSS system is about 20 dB, which is mainly caused by the aperture loss of 45° RTFG. Moreover, we have also investigated the spectral filtering performance of the proposed WSS, in which the filtered spectral of the channel spacing of 300 GHz, 200 GHz and 100 GHz are realized. The proposed in-fiber 45° RTFG diffraction device based WSS has a compact structure and C+L covered bandwidth, which can be potentially used for optical fiber communication.