InGaAs光敏元的暗电流是衡量探测器材料性能的一个重要指标。对于2.4μm延伸波长InGaAs，它的暗电流比1.7μm的要大2~3个数量级。文章简单介绍了InGaAs光敏芯片的暗电流、噪声和偏压的关系。光敏元的偏压越小，暗电流和噪声越小。侧重介绍了一种基于输入失调电压补偿的InGaAs暗电流抑制电路的结构。此电路有两种工作模式：失调电压补偿模式和不补偿模式。在补偿模式下，即使放大器两个输入端的失调电压达到28mV，光敏元两端电压通过补偿后可以降低到小于0.5mV。

The dark current of InGaAs is one important indicator for evaluating the performance of detector materials. For the InGaAs with the cutoff wavelength of 2.4μm, the dark current is two or three orders of magnitude larger than that of 1.7μm InGaAs. In this article, the relationship of the dark current, noise and bias voltage is briefly introduced. The dark current and noise become smaller under lower bias voltage. And then a circuit structure is presented in detail, which is based on input offset voltage compensation to suppress the dark current of InGaAs. The circuit has two work modes of offset voltage compensation mode and no compensation mode. With offset voltage compensation, the bias voltage of InGaAs can be brought down to be less than 0.5mV, even when the offset voltage of amplifier reaches 28mV.