Abstract
The first demonstration of single-mode behaviour of interband cascade lasers (ICLs) using a slotted waveguide is presented. Side mode suppression ratios (SMSRs) between 10-15 dB are observed for temperatures of 15-21.5°C for injection currents near the maximum before the thermal rollover and after this point. This provides a benchmark for the amount of modulation of the refractive index in the cladding required to interact with the longitudinal cavity modes. Threshold currents of 90 mA are achieved with an output power of 2.2 mW. This is an increase by 35 mA and a decrease by 7.8 mW from the Fabry-Pérot style ICLs with multi-mode output.