Author:
Fan 范 Wenjie 文杰,Liu 刘 Wenyao 文耀,Pan 潘 Ziwen 梓文,Wang 王 Rong 蓉,Liu 刘 Lai 来,Xing 邢 Enbo 恩博,Zhou 周 Yanru 彦汝,Tang 唐 Jun 军,Liu 刘 Jun 俊
Abstract
Mode locking can be effectively achieved by using the thermo-optic effects in the whispering gallery mode (WGM) optical microcavity, without the help of external equipment. Therefore, it has the advantages of small size, low integration costs, and self-locking, which shows great potential for application. However, the conventional single-channel microcavity thermal-locking method that relies solely on internal thermal balance will inevitably be disturbed by the external environment. This limitation affects the locking time and stability. Therefore, in this paper, we propose a new method for closed-loop thermal locking of a dual-channel microcavity. The thermal locking of the signal laser and the thermal regulation of the control laser are carried out respectively by synchronously drawing a dual-path tapered fiber. The theoretical model of the thermal dynamics of the dual-channel microcavity system is established, and the influence of the control-laser power on the thermal locking of the signal laser is confirmed. The deviation between the locking voltage of the signal laser and the set point value is used as a closed-loop feedback parameter to achieve long-term and highly stable mode locking of the signal laser. The results show that in the 2.63 h thermal-locking test, the locking stability is an order of magnitude higher than that of the single tapered fiber. This solution addresses the issue of thermal locking being disrupted by the external environment, and offers new possibilities for important applications such as spectroscopy and micro-optical sensor devices.