Optical gain, loss, and transparency current in high performance mid-infrared interband cascade lasers

Abstract

The net modal gain, optical loss, and transparency current of high-performance, narrow ridge waveguide interband cascade (IC) lasers have been measured using the Hakki–Paoli technique in the temperature range from T=78 to 270 K. In this temperature range, the optical loss of IC lasers increases from αw≈17 cm−1 at T=78 K to αw≈35 at T=270 K, the transparency current density rises from Itr=10 to 330 A∕cm2, and the differential gain decreases from gd≈2.2 cm∕A to gd≈0.06 cm∕A with a characteristic temperature of T0=130 K. The implications of these observed characteristics for IC lasers are discussed.