Ashim Kumar Saha

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

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

We demonstrate two-wavelength lasing in a simple all-active circular ring/Fabry–Perot composite cavity GaAsP laser with two separate p-electrodes. Two-wavelength lasing of almost equal power with 3.3–7.5 mW total output under continuous wave operation was accomplished by controlling the currents injected into the Fabry–Perot (FP) section and the ring section independently. Discrete sets of wavelength separations of 1.0–4.3 nm in the 800 nm band were obtained as expected by the theoretical considerations. The corresponding beat frequencies of 0.5–2.0 THz are suitable for photomixing generation of THz waves.

Demonstration of Two-Wavelength Lasing in a GaAsP Ring/Fabry-Perot Composite Cavity Semiconductor Laser

We demonstrate two-wavelength lasing in a circular ring / FP composite cavity GaAsP laser with two separate p-electrodes. Lasing of 1.0~4.3 nm wavelength separation and almost equal powers (total ~7.5 mW) under CW operation was accomplished by controlling the currents injection to the FP and ring sections independently.