Electrical thermo-optic tuning of ultrahigh-Q silica microsphere with laser-induced graphene

Abstract

We propose a scheme to achieve ultrahigh-quality (Q) silica microsphere electrical thermo-optic fully tunable tuning, which can keep its Q factor of around 108 during the tuning process. In this work, the rod of the silica microsphere is fixed on laser-induced graphene (LIG). The large amount of Joule heating generated by LIG energization can be effectively transferred to the microsphere, thus can achieve a wide range of electrical thermo-optic tuning. Experiment results show that such a simple and low-cost device owns an ultrahigh-Q factor of around 108, an extensive tuning range of 3.03 nm, a sensitivity of 15.37 pm/°C. Its tunable range is 2.5 times greater than its azimuthal FSR. This practical scheme keeps ultrahigh-Q factors and achieves fully tunable tuning without introducing complex processes and additional instrumentations, which has great potential for tunable filters and optical switches.