1.3 μm InGaAsN quantum well vertical cavity surface emitting lasers on GaAs substrates

We report characteristics of 1.3 μm electrically pumped InGaAsN quantum well VCSELs grown on GaAs. The epitaxial structure was grown by MBE in a single growth run using in-situ optical reflectance feedback control to accurately control layer thicknesses. The top and bottom distributed Bragg reflector mirrors contained 28 and 33 periods, respectively. With the exception of a single period of the upper mirror nearest the cavity, both mirrors were doped n-type to reduce free carrier absorption losses. A reverse-biased GaAs tunnel diode provided a high-conductivity transition between n- and p-type regions of the upper mirror. Electrical and optical confinement were provided by selectively oxidized AlAs layers adjacent to the cavity. CW room-temperature lasing was obtained in these devices at wavelengths as long as 1294 nm, while pulsed lasing was obtained at wavelengths as long as 1305 nm. A side mode suppression of 28 dB is observed in devices operating CW at slightly shorter wavelengths. A maximum single mode output power of 140 μW at 1289 nm was obtained at 20°C and continuous wave operation was observed up to 50°C. VCSELs operated with threshold currents varying from 1.5 to 7 mA. Equivalent threshold current densities were as low as 4 kA/cm₂. Open eye diagrams were obtained for devices driven on-wafer with pseudo-random bit sequences at 2.5 Gb/s. With modifications to the mirror design to lower the device voltage and modest improvements to the InGaAsN quality, we expect significantly improved optical and electrical performance