3.36 µm single-mode quantum cascade laser with a dissipation below 250 mW.

We present 3.36 µm buried heterostructure distributed-feedback quantum cascade lasers with a power dissipation at threshold below 250 mW and operation temperatures as high as 130 °C. Threshold values below 20 mA at -10 °C in pulsed operation and 30 mA at -20 °C in continuous-wave operation are reported. Optical power above 130 mW and 13 mW are achieved at -20 °C in pulsed and continuous-wave operation, respectively. Continuous-wave operation occurs until 15 °C. We show single-mode emission in pulsed and continuous-wave operation. Single-mode performance is demonstrated in long pulse (5.56 µs) operation. The laser far-field exhibits a single lobe emission with full-width-half-max of 27 ° × 34 °.

Broadband superluminescence, 5.9 µm to 7.2 µm, of a quantum cascade gain device.

The broadband electroluminescence of a quantum cascade device based on a multi-color active region covering the wavelengths 5.9 µm - 7.2 µm was measured. Anti-reflection coatings were applied on both cleaved facets to remove the Fabry-Pérot cavity and prevent the device from lasing. This allows the latter to be studied either as a superluminescent diode or a single-pass amplifier in order to determine its suitability as a source for low speckle imaging applications. At 243 K, the amplified spontaneous emission has a peak power of 38 µW that agrees well with a simple model of spontaneous emission intensity. The light of a similar structure could be modulated up to 1 GHz, limited by the RC constant of the device. The peak gain was measured from high-resolution luminescence spectra and determined to be 6.3 cm⁻¹, corresponding to a single-pass gain of 1.89.