Analog light signal based opto-electronic ring-oscillator and tunable oscillation frequency

Abstract

This paper demonstrates opto-electronic ring-oscillator constructed by an odd number of opto-electronic inverters for the digital (electric) and analog (light) signals based on mixed-signal communications. The opto-electronic inverter is consisting of light-emitting and light-receiving parts which can be regarded as a digital-to-analog and an analog-to-digital converters, respectively. To investigate the light-signal processing properties, the oscillation frequency (fosc) studies were performed by controlling three different parameters of load resistors (RL), light wavelengths (λ), and photosensor type. The smaller RL or the shorter λ of the light signal brings the faster fosc in opto-electronic ring-oscillator. In addition, the photodiode-based opto-electronic ring-oscillator shows much faster signal processing characteristics than the case of CdS sensor. Our opto-electronic ring-oscillators show a wide range of tunable fosc from 0.92 Hz to 114.42 Hz; moreover, it shows small signal-like light transfer characteristics as an analog signal process that can be useful in future opto-electronic device applications.