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.