Gain-coupled distributed feedback laser based on periodic surface anode canals

Development of a High-Power Surface Grating Tunable Distributed-Feedback Bragg Semiconductor Laser Based on Gain-Coupling Effect

Lasers used for space communication, lidar, and laser detection in space-air-ground integration applications typically use a traditional 1550 nm band tunable distributed-feedback Bragg (DFB) semiconductor laser. This has low output power, complex fabrication process, and high fabrication cost. In this paper, we present a gain-coupled surface grating-based 1550 nm DFB semiconductor laser that can be fabricated without the use of secondary epitaxial growth techniques or high-precision lithography. The periodic electrical injection is used to achieve a gain coupling effect. A tapered waveguide is added to achieve a high output power, and the use of AlGaInAs multiple quantum wells in the active region reduces the linewidth of the laser. A continuous-wave (CW)output power of 401.5 mW is achieved at 20 °C, the maximum side mode rejection ratio exceeds 55 dB, the measured 3 dB linewidth is 18.86 MHz, and the stable single-mode output with a quasi-continuous tuning range of 6.156 nm near 1550 nm from 10 °C to 50 °C. This simple preparation method, low cost, excellent performance, and stable tunable laser have extremely high commercial value in applications such as space communication, lidar, and laser detection.

996 nm high-power single-longitudinal-mode tapered gain-coupled distributed feedback laser diodes

A high-power single-longitudinal-mode regrowth-free tapered gain-coupled distributed feedback laser diode based on periodic current injection is achieved at 996 nm. It enhances the output power without beam quality degrading. A continuous-wave output power of over 1.12 W is achieved at 3 A. The maximum output power in single-longitudinal-mode operation is up to 0.56 W at 1.4 A. The power conversion efficiency is over 24%, and the slope efficiency is 0.58 W/A. The side mode suppression ratio is over 38 dB; the 3 dB spectral linewidth is less than 2.4 pm. The lateral far-field divergence angle is only 14.98°, and the beam quality factor M² is 1.64, achieving a near-diffraction-limit emission. Our device has great potential in commercial applications and the experimental study of high-power near-diffraction-limit laser diodes for its low-cost fabrication technique and narrowband single-longitudinal-mode emission at high power.