Temperature controllable optical switch for erbium-doped random fiber laser

Abstract

Different from the conventional optical switches, a rapid response and simple structure of erbium-doped random fiber laser for optical switch is presented. The random fiber laser (RFL) was achieved by pumping an erbium-doped fiber connected with tens of kilometers of single-mode-fiber (SMF). Meanwhile, the 1 cm-long photonic crystal fiber (PCF) filled with a liquid crystal (LC), which is spliced after the reflected output port of a 980/1550 nm wavelength division multiplexing (WDM) coupler, is used as the sensing unit. A high-extinction ratio more than 36 dB over a wavelength range from 1529.00 nm to 1533.16 nm can be observed when the temperature increases from 60 °C to 61 °C. The high-extinction ratio RFL is caused by the reduction of refractive index of the LC-filled PCF (LCPCF). Under the action of the band gap guiding mechanism, the LC molecules in PCF change from each anisotropic to each isotropic when the temperature increases from 60 °C to 61 °C, which induces thermo-optical switch of the LCPCF. The optical switch of erbium-doped fiber random fiber laser has the best comprehensive performance with low cost, high sensitivity, strong anti-electromagnetic interference ability based on control of the temperature.