用于径向速度测量精确校准的laser频率梳频谱平坦化的全光子动态装置
An all-photonic, dynamic device for flattening the spectrum of a laser frequency comb for precise calibration of radial velocity measurements
摘要：
激光频率梳正迅速成为达到最高径向速度精度的关键。一个缺点是梳状线在光谱上的亮度变化很大（高达4-5个数量级）。这可能导致某些线路饱和，而其他线路处于低信号并在噪声中丢失。由于这些效应中的任何一个而损失线会降低精度，从而降低梳的有效性。此外，梳线的亮度会随时间变化，这会将具有初始合理SNR的梳线驱动到上述两种状态。为了减轻这两种效应，激光频率梳使用光学滤波器。平坦器是典型的体光学装置，其用光栅分散梳状光，然后在将光重新组合到另一个单模光纤中并将其发送到光谱仪之前使用空间光调制器来控制整个光谱的振幅。这些装置可能很大（小台面），昂贵（几十万美元），稳定性有限。为了解决这些问题，我们已经开发了一个全光子频谱芯片。该器件由SiN芯片上的光波导构成。来自激光频率梳的输出光纤的光可以直接连接到芯片，其中光首先使用阵列波导光栅分散。为了控制每个通道的亮度，光在与第二阵列波导光栅重新组合之前通过马赫-曾德尔干涉仪。热光相位调制器在复合之前用于每个通道中，以根据需要匹配通道的路径长度。在这里，我们介绍了我们的第一代原型的结果。该器件的工作波长为1400-1800 nm（覆盖H波段），具有20、20 nm宽的通道。
英文摘要：
Laser frequency combs are fast becoming critical to reaching the highest radial velocity precisions. One shortcoming is the highly variable brightness of the comb lines across the spectrum (up to 4-5 orders of magnitude). This can result in some lines saturating while others are at low signal and lost in the noise. Losing lines to either of these effects reduces the precision and hence effectiveness of the comb. In addition, the brightness of the comb lines can vary with time which could drive comb lines with initially reasonable SNR's into the two regimes described above. To mitigate these two effects, laser frequency combs use optical flattener's. Flattener's are typically bulk optic setups that disperse the comb light with a grating, and then use a spatial light modulator to control the amplitude across the spectrum before recombining the light into another single mode fiber and sending it to the spectrograph. These setups can be large (small bench top), expensive (several hundred thousand dollars) and have limited stability. To address these issues, we have developed an all-photonic spectrum flattener on a chip. The device is constructed from optical waveguides on a SiN chip. The light from the laser frequency comb's output optical fiber can be directly connected to the chip, where the light is first dispersed using an arrayed waveguide grating. To control the brightness of each channel, the light is passed through a Mach-Zehnder interferometer before being recombined with a second arrayed waveguide grating. Thermo-optic phase modulators are used in each channel before recombination to path length match the channels as needed. Here we present the results from our first generation prototype. The device operates from 1400-1800 nm (covering the H band), with 20, 20 nm wide channels.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
