| 摘要 |
<p>An optical receiver has a pre-amplifier stage (12) comprising an FET-FET cascode circuit (10). For coherent detection, an electrical local oscillator signal is applied to the gate of one of the FETs (10', 10''), the frequency of which is chosen to provide either homodyne demodulation, or a second IF signal. For direct detection the cascode consists of a dual gate FET (10), which is also the preferred form of cascode for coherent detection.</p> |
