990 nm High-Power High-Beam-Quality DFB Laser With Narrow Linewidth Controlled by Gain-Coupled Effect

Abstract

High-power single-longitudinal-mode regrowth-free gain-coupled distributed feedback laser diode based on ridge waveguide with periodic current injection is achieved at 990 nm. Our device is fabricated only by standard i-line lithography with micron-scale precision, obtains an excellent performance at high injection current. A continuous-wave power of over 0.681 W is achieved at 3 A. The maximum continuous-wave power at singlelongitudinal-mode operation is up to 0.303 W at 1.4 A. Narrow linewidth emission has been reached with a 3 dB spectrum width less than 1.41 pm. The high side mode suppression ratio is over 35 dB. The lateral far field divergence angle is only 15.05°, the beam quality factor M 2 is 1.245, achieving a laterally near-diffraction-limit emission. It is more beneficial for single-mode fiber coupling as pumping sources and other applications which require high beam quality at high power with easy fabrication technique.

Spatial and spectral filtering of tapered lasers by using tapered distributed Bragg reflector grating

“…[1,2] Such lasers use a ridge waveguide (RW) to provide a lateral single-mode emission and amplify the output power without degrading the beam quality by a tapered amplifier (TA). Meanwhile, the distributed Bragg reflector (DBR) [3][4][5] or distributed feedback (DFB) [6][7][8] grating is used to narrow the spectral linewidth. However, because the width of the front facet is much larger than that of the RW, the side backward-traveling waves is formed due to the residual reflection of the TA section, which leads to the parasitic oscillation adjacent to the RW section and destroys the performance of the laser.…”

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

“…In our previous studies, gain-coupled DFB semiconductor lasers with wavelengths of 795 nm, 905 nm, 990 nm, and 1045 nm were fabricated based on periodic electrodes windows and surface grating structures [17][18][19][20]. The periodic electrical injection of the surface p-electrode caused the quantum wells in the active region to generate periodic gain differences to realize the gain coupling effect and enable the device to achieve stable single longitudinal mode output [21][22][23].…”