A New High Efficiency Optical-Microwave Double Mixing Method

Abstract

The widely used optical receivers apply mainly photodiodes to detect the optical intensity modulated signal. A relatively high sensitivity is achieved by properly matched transimpedance or distributed amplifiers [1-3]. In another method the modulated optical signal is mixed with a microwave signal in the photodiode producing an intermediate frequency signal [4-11]. Thus, heterodyne type reception is feasible. However, the mixing conversion has a higher loss compared to the direct detection. In the new optical-microwave double mixing approach the conversion loss is much less than that of the direct detection offering a significant improvement in the reception sensitivity. The mixing product is even further increased by resonant enhancement providing 30 dB improvement in comparison to direct detection.