Highly unidirectional Y-junction-coupled S-section quantum-dot ring lasers

Abstract

Fabrication and characterization of Y-junction-coupled S-section InAs/InGaAs/GaAs quantum-dot ring lasers with high unidirectionality is reported. Stable unidirectional operation of the ring lasers is ensured by a new design that suppresses the unwanted counterpropagating modes more effectively than it was possible in the previous S-section-racetrack design.

Single-mode operation of GaAsP ring/Fabry–Perot composite cavity semiconductor lasers

“…Control of the lasing direction was accomplished either with external optical injection 14) or special designs using selective electrical pumping. 15) Most recently a square ring=FP composite cavity laser, where deeply etched total internal reflector mirrors and a multimode interference (MMI) coupler were used to form a ring cavity and couple it with the FP cavity, was reported, 16) but the fabrication process was complex.…”

Toward a Feedback-Insensitive Semiconductor Laser

“…Another interesting line of research is found in refs. [24], [25] and [28] and involves the so-called S-ring laser, in which a cross-over waveguide connects two opposite sides of the ring, guiding light from one sense of rotation into the other, but not the other way around. Under lasing conditions, this topology favors directional operation, where the ratio of clockwise (CW) to counter clockwise (CCW) output power is observed as large as 13 dB in Hohimer et al [24], 25 dB in Cao et al [25] and 30 dB in Withers et al [28].…”

“…[24], [25] and [28] and involves the so-called S-ring laser, in which a cross-over waveguide connects two opposite sides of the ring, guiding light from one sense of rotation into the other, but not the other way around. Under lasing conditions, this topology favors directional operation, where the ratio of clockwise (CW) to counter clockwise (CCW) output power is observed as large as 13 dB in Hohimer et al [24], 25 dB in Cao et al [25] and 30 dB in Withers et al [28]. The S-shaped micro laser idea was revived in Ren et al [38], where two of these lasers are coupled and operated under PT-symmetric conditions so as to achieve unidirectional single-mode operation.…”

Two-wavelength lasing of ring/Fabry–Perot composite cavity semiconductor laser with two separate electrodes

“…Hence, low-cost devices with simple fabrication processes are still required. Semiconductor ring lasers require relatively simple fabrication processes [19][20][21][22][23] compared with the grating-incorporated lasers. Devices having various configurations were studied to control the lasing of one of the two counter propagating modes 21) as well as the enhancement of light out coupling from the ring cavity.…”

“…Semiconductor ring lasers require relatively simple fabrication processes [19][20][21][22][23] compared with the grating-incorporated lasers. Devices having various configurations were studied to control the lasing of one of the two counter propagating modes 21) as well as the enhancement of light out coupling from the ring cavity. 22) We recently reported the experimental demonstration of the stable single-mode operation of a circular ring=FP (RFP) composite cavity laser.…”