| 摘要 |
<p>A thermally stabilized optical preamplifier includes a first transimpedance amplifier 15 which receives a photosignal current from a photodiode 16. The gate of a GaAs device 18 is the input to the first transimpedance amplifier, and the drain is coupled to a source of constant current 20. Also coupled to the drain of the GaAs device is a common base stage 22,24,26,28, and the gain of the first transimpedance amplifier is set by a resistor 30 coupled between the input of the first transimpedance amplifier and the output of the common base stage. A current setting resistor 40 coupled to the output of the first transimpedance amplifier converts output voltage to current, which is summed with a compensating current in a second transimpedance amplifier 42. The compensating current consists of a variable current generator 36 and a thermal current generator 35 which compensate for the current produced by the absolute value and thermal characteristics of the gate to source voltage of the input GaAs device.</p> |
