Single-Mode Electrically Pumped Liquid Crystal VCSELs with Mode-Hop-Free Tuning over 30 nm

Electrically pumped liquid crystal (LC) tunable VCSELs hold transformative potential for optical coherence tomography (OCT), spectroscopy, LiDAR, and high-speed optical communications. However, conventional optical pumping LC systems suffer from bulkiness, inflexibility, and scalability limitations. Herein, we propose a fully electrically pumped LC-tunable VCSEL (ELC-VCSEL) with a three-electrode design and an inner LC-coupled cavity. Through COMSOL simulations and structural optimization, we comprehensively evaluated the effects of mode competition and LC birefringence characteristics on the wavelength tuning range. This device achieves a 30.8 nm mode-hop-free tuning range (1044.5–1075.3 nm) at 3 mA via a precisely designed LC modulation layer that suppresses mode competition. Simultaneously, the proposed ELC-VCSEL exhibits excellent single-mode characteristics, with a side-mode suppression ratio (SMSR) of 33.7 dB and a full width at half maximum (FWHM) of 0.19 nm. By eliminating external pumping to reduce costs and power consumption, the ELC-VCSEL could further expand its practical applicability in electro-optic systems, biomedical sensing, optical communications, and fast-response optical instruments.