Improvement Of Temperature Performance Research Articles

Continuous-wave operation of a 1.3 μm wavelength npn AlGaInAs/InP transistor laser up to 90 °C

A transistor laser (TL) is a device that operates at a high-speed with multiple functions such as output control with low wavelength shift and signal mixing. By adopting a high heat dissipation structure with a high-speed compatible wide electrode pad and thick Au plating in TLs, improvement of temperature performance in 1.3 μm wavelength npn AlGaInAs/InP TL was demonstrated. As a result, continuous-wave operation of a 1.3 μm TL up to 90 °C was achieved. The thermal resistance was estimated to be 25 K W−1, based on the spectrum behavior, which is at least four times lower than the previously observed value.

Terahertz quantum cascade lasers with double-resonant-phonon depopulation

We present two different terahertz quantum cascade laser (QCL) designs based on GaAs∕Al0.3Ga0.7As heterostructures that feature a depopulation mechanism of two longitudinal-optical phonon scattering events. This scheme is intended to improve high temperature operation by reducing thermal backfilling of the lower radiative state. The better of these two devices displays a threshold current density of 170A∕cm2 at 5K and lases up to 138K in pulsed mode and 105K in continuous-wave mode. However, contrary to expectation, we observed no improvement in temperature performance compared to single-resonant-phonon designs, which suggests that the thermal backfilling is not yet a limiting factor for high temperature terahertz QCL operation.