The gain switching and active mode locking of mid-infrared quantum cascade (QC) lasers was analyzed. A step-recovery diode that produced voltage pulses of approximately 90 ps at a repetition rate of 100 MHz to gain switch several QC lasers was used. A pulse duration of 89 ps was obtained accounting for the finite response time of the detection electronics. In the case of active mode locking, a 8-μm device with round-trip frequency of 11.65 GHz was used. The phase-locking of this multimode output was confirmed by the observation of a narrow spike centered at frt in the rf spectrum of quantum well infrared photodetector (QWIP) photocurrent.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering