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.

单波长激光通信终端之间数据通信时，信号传输与接收间良好的隔离性能是建立双工双向激光通信的关键。本文针对单个激光波长激光通信端机的传输与接收方案，以及激光通信终端整体的通信性能，分析了关键元器件的表面粗糙度和表面清洁度水平对激光通信终端隔离性能的影响。通过Harvey模型、ABg模型推导模型参数。利用TracePro软件对所设计的方案进行分析。得出以下结论：当信号传输通道中λ/2波片、λ/4波片和光学天线结构的表面粗糙度变好或者表面清洁度提升时，元件带来的后向散射会降低信号传输通道内的隔离性能。同时，激光通信终端隔离度的测量结果为77.86 dB，与软件仿真结果78.35 dB基本一致，这一结果可以应用于激光通信系统。

为了获得数字微镜器件（DMD）的真实光学特性，提出了微镜单元杂散光分布测试方法，并搭建实验装置对2×2阵列区域微镜单元的杂散光分布情况进行测试。提出了一种杂散光测试方法，并针对微镜单元尺寸小、配置方式灵活的特点，设计了汇聚光斑大小连续可调的照明系统以及可以对微镜单元清晰成像的成像系统。通过实验得到了2×2阵列区域微镜单元的杂散光分布情况。测试结果表明，单个微镜单元中心孔道位置附近反射的能量较强，靠近边缘位置反射的能量则相对较弱。此外，测试区域之外的微镜单元也会反射一部分能量，测试区域内微镜单元杂散光绝对强度最大值出现在中心孔道附近，其灰度值为6.86，紧邻测试区域微镜单元杂散光绝对强度最大值同样也出现在中心孔道附近，其灰度值为4.01，由此可以说明中心孔道位置附近的杂散光较强；测试区域内微镜单元的杂散光相对强度相对较弱，从测试区域边缘开始急剧增大，经过大约两个微镜单元后达到峰值，数值为293.5%，此后开始急剧下降。

针对数字微镜器件（digital micromirror device，DMD）衍射效应对系统成像影响严重的问题，对DMD元件产生的杂散光进行研究。基于严格耦合波理论构建了DMD衍射模型，分析不同波段和入射角度对其衍射效率的影响，分析结果表明，在长波红外波段DMD衍射效应较明显，且随着入射角度增大，DMD衍射效应更为显著。分析投影系统中DMD的衍射杂光产生途径，通过改变系统的F数来控制入射角度，计算出DMD衍射效应产生的杂光能量占比，给出不同波长下，不同F数的光学系统杂光随衍射效应的变化曲线，即F数越大，DMD衍射效应对系统杂光影响越小。

由于全景环带光学系统的头部单元结构形式复杂，内部光路经过多次反射与折射，杂散光情况比较严重，因此全景环带光学系统设计过程中对杂散光的分析尤为重要。文中着重分析全景环带光学系统头部单元中产生杂散光的形式，对未经全景环带光学系统头部单元反射的杂散光建立消杂光数学模型，在此基础上对全景环带光学系统行了优化设计；对全景环带光学系统中头部单元胶合面反射的杂散光采用一种凸向像面的弯月胶合镜的形式进行抑制，并通过ASAP软件建模仿真。仿真结果显示，杂散光能量降低90%，证明采用的结构形式和消杂光数学模型有效地抑制了杂散光的产生。