Tunable Laser Using Transverse Cavity Surface Emitting Laser Working near Exceptional Point

Vertical-cavity surface-emitting laser (VCSEL) has proven value in data communication, optical links, optical sensing, laser printing, and optical computing for its advantages in fabrication cost, energy consumption, temperature stability, and dense-array fabrication complexity. However, the limit of wavelength tunability of VCSEL restricts its application in key areas. Here, we propose a transverse cavity surface emitting laser (TCSEL) with a highly tunable wavelength assisted by a coupled feedback cavity. We presented a prototype bowtie-shaped transversely coupled cavity that emits a laser at 980 nm. Via controlling the injection current in one cavity and the negative bias voltage in the other cavity, we can maneuver the gain and loss and achieve robust wavelength tuning of up to about 5 nm experimentally. Our results represent a significant advancement in VCSEL/TCSEL technology enables a more compact and efficient wavelength tuning scheme for applications in optical communication and sensing.