| Summary: | 碩士 === 國立暨南國際大學 === 電機工程學系 === 92 === In this thesis, the optical detecting system including the optical receiver and transmitter is realized. We use the cascode operational amplifier, the rail-to-rail operational amplifier, and the current mirror amplifier to implement the optical detecting system through the chip-implementation-center(CIC).
The optical detecting system is often applied to detect the optical signal in the severe disturbance of the ambient light. The disturbance of ambient light makes the weaker optical signal undetectable. Therefore, the optical receiver, which rejects ambient light, is constituted by the transimpedance amplifier with a integrator to lower the optical detecting system’s sensitivity to the ambient light.
A laser diode have some advantages including the mono-chromaticity、directionality、brightness and coherence. Therefore, a laser diode is used as a optical source in the optical detecting system. The laser driver is designed with a signal modulation circuit and a automatic power control circuit. The signal modulation circuit makes the laser diode radiate optical signal, and the automatic power control circuit stabilizes the laser diode radiated optical power in the variable power supply. In the thesis, the laser diode radiates signal current, ΔIP-P(max)≒5.6mA. The automatic power control stabilizes the current variation at +150mV and -150mV when the maximum variation of power supply are +0.7mA and -0.75mA, respectively.
The optical detecting system combined with the optical receiver and transmitter is implemented for the measurement of optical signal and optical power. The optical power is divided into the DC and AC power. The maximum DC and AC power radiated by the laser diode are 5mW and 4.86mW, respectively. The maximum DC and AC power detected by the photodiode are 4.11mW and 4.14mW, respectively.
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