Shortened injector interband cascade lasers for 3.3- to 3.6-μm emission

Abstract

Interband cascade lasers (ICLs) are very attractive light sources to cover the important spectral range from 3.3 to 3.6 µm, which is of major interest for hydrocarbon detection. We present ICLs emitting in this wavelength range that have a notably shortened injector region. Compared to a well-established reference design, the total length of one cascade is reduced by about 16% to only 63 nm. The benefits are a reduction of the number of heterointerfaces, a higher intensity of the optical mode in the active region, and easier strain compensation. Threshold current densities of devices using the new injector design are cut in half throughout the temperature range of operation, compared to devices with the reference design. Deeply etched ridge waveguide devices processed from structures with 14 cascades yielded maximum operation temperatures of 73°C in pulsed operation. Peak output powers exceed 100 mW at a heat-sink temperature of 15°C.