Abstract

We present the results of experimental and theoretical study of onset and development of regenerative oscillations (RO) consistent with competition between electronic and thermal dispersive nonlinearities in a bistable semiconductor cavity and observed previously for several semiconductors^{[1, 2]}. As an experimental object we used the InSb cavity excited by COlaser with λ = 5.6-6 µ at T = 80-100 K. Depending on initial cavity detuning δ we firstly observed soft and sudden onset of RO. In the soft case (Fig. 1 a) occurred at δ~ 0 achievement of some threshold power P₀^th led to onset of small amplitude near harmonic RO with the period of 0.1-0.5 msec. Further increase of Po resulted in gradual rise of period (up to 3 sec) and amplitude and transition from near harmonic to pronounced relaxation shape of RO. Oscillations amplitude was proportional to (P₀-P₀^th)^1/2 in the whole region of measurements. We also observed hysteresis between oscillatory and stable states (Fig. la). At high enough 8 we registered sudden onset of RO with finite amplitude and period about fractions of seconds (Fig. lb). In this case RO appeared at higher input compared with the P₀^th for the soft case. In the both cases return to stable state with decrease of Po took place without hysteresis.

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