Overview: In order to achieve the measurement of gravitational wave signals in the millihertz frequency band, the space-based gravitational wave detection projects such as LISA, TianQin, and Taiji projects, which are based on laser interference systems, require the hardware noise floor of the interferometers to be lower than the interstellar weak light shot noise limit. This imposes stringent engineering specifications on the optical-mechanical design and the corresponding interferometer payload. This paper approaches the issue from the perspective of detection mode selection and derives the expressions of readout noise and stray light noise in the interference signal under the single detector mode and the balanced mode. Furthermore, a detailed discussion is provided on the weak-light interference process of the scientific interferometer. The results demonstrate that the balanced mode is capable of suppressing the interference phase noise caused by laser power fluctuations and backscattered stray light across multiple orders of magnitude. However, the suppression capability is constrained by the unequal splitting property of the beam combiner. To address this, a relative gain factor is introduced to compensate for the unequal splitting property of the beam combiner. Further analysis reveals that electronic gain compensation can only eliminate the impact of unequal splitting on one of the two noises rather than both simultaneously. Therefore, a balance must be struck in selecting gain compensation between the suppression of laser power fluctuation noise and stray light noise. Even with this consideration, the balanced mode still offers significant noise suppression capabilities at a magnitude difference, thus potentially reducing the engineering requirements for laser power fluctuations and telescope backscattered stray light.

成功设计了一款天文应用的640×512短波红外焦平面读出电路。由于红外天文观测具有极低背景辐射、光子通量低的特点，为了实现探测器的高信噪比，需要降低器件的暗电流和电路噪声。电路采用有效的功耗管理策略，在保证电路正常工作的前提下尽可能地降低电路功耗以减小电路辉光对器件暗电流的影响。同时，研究非破坏性读出的数字功能，实现了超长的积分时间和信号的多帧累积,并作为一种斜坡采样的策略有效地降低读出噪声。短波HgCdTe焦平面的测试结果符合理论设计预期，开启电路非破坏性读出功能，设置6000 s的积分时间，当电路功耗调低至14.04 mW时暗电流为0.9 e-·pixel⁻¹·s⁻¹。读出噪声在两档增益下分别为50 e-（10 fF）和27 e-（5 fF），非线性度低于0.1%。

基于天文红外探测器评价体系，利用改进的“光子转移曲线”测试方法，分别测试了液氮制冷和热电制冷的两款InGaAs近红外探测器的性能。NIRvana-LN光电子与输出数字量的转换因子为0.16ADU/e^-，读出噪声实测值是83 e^-，远高于标称值15 e^-；NIRvana的高、低转换因子分别为1.25ADU/e^-和0.097ADU/e^-，读出噪声分别为105 e^-和380 e^-；NIRvana在高转换因子档下暗电流实测值是415 e^-/s，大约是标称值的2倍。理论估算云南天文台两米环形望远镜在1.565 μm太阳磁场测量时的信号电子数约8800 e^-，在实测暗电流4.06 e^-/s，像元曝光时间20 ms，读出噪声83.59 e^-条件下，NIRvana-LN探测器信噪比为70。