Radically Uniform Spike Trains in Optically Injected Quantum Cascade Oscillators

TL;DR

This paper reports the experimental observation of highly uniform spike trains in an optically injected quantum cascade laser, attributing this uniformity to the ultrashort carrier lifetime of the gain medium.

Contribution

It demonstrates for the first time that quantum cascade lasers can produce highly uniform spike trains due to their ultrashort carrier lifetime, supported by theoretical analysis.

Findings

Observation of highly uniform spike trains in quantum cascade lasers

Attribution of uniformity to ultrashort carrier lifetime

Experimental and theoretical validation of spike train behavior

Abstract

It has been found that noise-induced excitability in quantum well and quantum dot semiconductor laser systems usually produces spike patterns of non-uniform amplitude. In this letter, we experimentally record that an inter-subband quantum cascade laser injected with a monochromatic laser exhibits a series of highly-uniform spike trains in the time domain. Theoretical analysis demonstrates that such high uniformity has its origin in the ultrashort carrier lifetime of the quantum cascade laser gain medium that is typically close to one picosecond.