Theory of delay-coupled non-identical quantum cascade lasers

摘要

It is shown that dynamics of delay-coupled quantum cascade lasers can be described in good approximation by the simpler set of rate equations for conventional interband diode lasers. A comparison of the steady-state solutions for locking shows excellent agreement with results obtained by time integrations of the full rate equations. The delay introduces an effective coupling phase equal to the product of operation frequency and delay time and the detuning width of the locking range is shown to periodically change when the delay time changes over an interval equal to half of the operation oscillation period.