Abstract

The dynamic behavior of hybrid bistable systems has been studied widely. Self-pulsing in the transmitted intensity has been predicted and observed whenever the feedback loop is affected by a sufficiently long delay.¹ Here we show that instabilities can also arise from the inclusion of an amplifier in the feedback loop. An amplifier is necessary, in general, to close the loop between the detector whose typical signal amplitude is hundreds of millivolts and the nonlinear device (electrooptic or acoustooptic modulator), which requires higher voltages to operate. We use a typical hybrid system² with an acoustooptic modulator (AOM). The output intensity is detected by a photodiode whose output is amplified and sent back into the driver of the AOM with no further delays except those introduced by the wires (30 cm). We study the dynamic behavior of the system for different amplifier gain and bandwidth. We present evidence of Hopf bifurcations, period doubling, deterministic chaos, and collisions of stable and unstable orbits.

© 1988 Optical Society of America