A tunable all-fiber filter based on microfiber loop resonator Available to Purchase

In this paper, a tunable high finesse microfilter is described, which is based on microfiber loop resonator (MLR). The length of microfiber loop could be controlled by a small cylindrical piezoelectric ceramic. As we calculated, this resonator has the maximum $Q$ factor of 2400 and the finesse of 4.3. MLR filter was demonstrated that the maximum extinction ratio is about $10dB$⁠, and the free spectral range variation range could be more than $100GHz$⁠. This device could also be integrated into a smaller size due to the bigger radius of curvature of the microfiber.