Extended electrical tuning of quantum cascade lasers with digital concatenated gratings

摘要

In this report, the sampled grating distributed feedback laser architecture is modified with digital concatenated gratings to partially compensate for the wavelength dependence of optical gain in a standard high efficiency quantum cascade laser core. This allows equalization of laser threshold over a wide wavelength range and demonstration of wide electrical tuning. With only two control currents, a full tuning range of 500nm (236cm~(-1)) has been demonstrated. Emission is single mode, with a side mode suppression of ＞20dB.