Single-mode interband cascade lasers emitting below 2.8 μm

In this work, single-mode distributed feedback (DFB) interband cascade laser (ICL) devices with record short wavelength emission below 2.8 mu m are presented. Pulsed measurements based on broad area laser devices with a cavity of 2mm length and 150 mu m width showed threshold current densities of 383 A/cm(2) at T = 20 degrees C and a characteristic temperature T-0 of 67 K. Fabricated DFB devices were operated in continuous wave mode at room temperature, with threshold currents of 57mA and demonstrated side mode suppression ratios of larger than 25 dB. The devices showed current tuning ranges of 7 nm and total (including drive current and temperature) tuning ranges of 12 nm, with respective tuning rates of 21 nm/W, 0.13 nm/mA and 0.29 nm/K. Using the full spectral gain bandwidth of the underlying ICL material, single-mode DFB emission was observed within a wavelength range of 150 nm utilizing different DFB grating periods. (C) 2015 AIP Publishing LLC.