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

Abstract

We designed and fabricated ring/Fabry–Perot composite cavity semiconductor lasers. Single-mode lasing under CW operation was accomplished. The threshold current was 140 mA, and an output power of 12 mW was obtained at an injection current of 250 mA. A side-mode suppression ratio (SMSR) higher than 25 dB was also obtained. The temperature coefficient of the lasing wavelength of 0.23 nm/°C was explained by considering the temperature coefficient of the bandgap energy of the quantum well.

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

“…A ridge channel waveguide using a GaAs 0.86 P 0.14 tensiley strained single-quantum-well separate confinement heterostructure (SQW-SCH) was designed. 23) Lasing of TM mode of higher gain at wavelength ∼800 nm is expected. The ridge width and height were determined as 3.0 and 1.55 µm, respectively.…”

“…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.…”

“…22) We recently reported the experimental demonstration of the stable single-mode operation of a circular ring=FP (RFP) composite cavity laser. 23) In this paper, we report the design, fabrication, and experimental results of a simple RFP composite cavity semiconductor laser for two-wavelength emission. The entire waveguiding structure can be fabricated by a single etching step.…”

“…Figure 1 shows the schematic of the RFP laser geometry consisting of an active circular ring resonator coupled to an active straight channel waveguide by a tangential coupler. 23) The ring radius is R and the straight channel length is L. Ridge type single mode waveguides with same width are used for both of the ring and straight waveguides. Two separate pelectrodes are used to control the injection currents to the ring section (I R ) and straight section (I F ) independently.…”

“…2(a) and 2(b). It can be easily shown that the ring=FP mode pairs of minimum separation are arranged nearly periodically with an approximate period of 23) The FP…”