Instability Thresholds in General Nonlinear Ring Resonators

Abstract

By considering a passive ring cavity with linear absorption in the dispersive limit, a unified analysis is presented for tuning-optimized minimum instability thresholds; the treatment is general, allowing consideration of arbitrary material response times, cavity tuning and finesse. In the adiabatic limit (τ → 0) the results reduce to the usual Ikeda map. The case of long medium-response time (τ → ∞) is treated in some detail in the high-finesse limit; these conditions being of particular relevance to semiconductor laser amplifiers. It is found analytically that in the high-finesse limit, both optical bistability and self-pulsing instabilities should exhibit the same low-threshold behaviour. An analytical expression is derived for the ‘instability threshold curve’, A ² B against B for minimum A ², in the mapping limit.