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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28 mV,光敏元两端电压通过补偿后可以降低到小于0.5 mV。
The dark current of InGaAs photosensors is an important indicator of detector material performance. For 2.4 μm extension wavelength InGaAs, its dark current is 2 to 3 orders of magnitude larger than 1.7 μm. The article briefly introduces the dark current, noise and bias of InGaAs photosensitive chip. The smaller the bias voltage of the photosensor, the smaller the dark current and the noise. The structure of InGaAs dark current suppression circuit based on input offset voltage compensation is mainly introduced. This circuit has two modes of operation: offset voltage compensation mode and non-compensation mode. In offset mode, the offset voltage across the photosensor can be reduced to less than 0.5 mV, even after the offset voltage on both inputs of the amplifier reaches 28 mV.