Speaker
Description
The linewidth enhancement factor (LEF) is known as an important property of semiconductor lasers. Recently, it is gaining more interest due to its key role in frequency comb operation. However, as of yet existing techniques to measure the LEF are limited to sub-threshold bias or single-mode operation. Here, we introduce a novel and universally applicable method to directly obtain the spectrally resolved LEF of a running laser frequency comb. The technique utilizes a phase-sensitive single shot measurement scheme. We derive a theoretical model, which is investigated by extensive Maxwell-Bloch simulations and demonstrated in an experiment on a quantum cascade laser.