Switching between states of an intrinsic bistable device is usually accomplished by changing the input intensity II, increasing it above the switch-up value It or below the switch-down value With a constant input intensity satisfying I↓⪅ II < I↑, switching can be actuated by external pulses. Switch-on by a 10-ps, 600-nm, 1-nJ pulse in less than the 200-ps detector response time is attributed to screening of the GaAs free excitons by hot carriers. Switch-off in ≤20 ns by a 7-ns, 600-nm, 300-nJ pulse is attributed to heating the etalon and increasing I4, until it exceeds the constant II. Under certain con-ditions the competition between excitonic and thermal effects causes the etalon to switch on and off repeatedly in a relaxation oscillation fashion. These regenerative pulsations could be the basis of an all-optical oscillator. The transverse profile has been examined for switching actuated by intensity modulation of the input. Whole-beam switching is observed, i.e., when switch-on occurs, it occurs out to large radii simultaneously. Computer simulations show whole-beam switching for strong diffractive coupling but show radially dependent switching for weak diffraction, neglecting transverse diffusion. The same etalon emits a near-band-gap laser pulse when pumped sufficiently by an above-band-gap pulse, serving as a wavelength converter. All of these modes of operation of the GaAs etalon, i.e., switchable memory, oscillator, and wavelength converter, could be useful in all-optical logic and computing systems.