Self-excited oscillation and monostable operation of a bistable light emitting diode (BILED)

A new simple opto-electronic bistable device has been obtained by combining a light emitting diode (LED) and a photodetector (PD) with electronic feedback using a broad bandpass filter. This has interesting dynamic characteristics which are expected to have such various applications as optical oscillators, optical pulse generators and optical pulsewidth modulators. The dynamic characteristics are represented by second-order nonlinear differential equations. In the analyses of these nonlinear systems, instead of numerical analyses with a computer, an approximate analytical method devised for this purpose has been used. This method has been used for investigating the characteristics of the proposed device quantitatively. These include the frequency of oscillations, pulsewidths and hysteresis. The results of the analyses agree approximately with experimentally observed values, thus the dynamic characteristics of the proposed device can be explained.