A optical fiber double scrambler and mechanical agitator system for the Keck planet finder spectrograph
A optical fiber double scrambler and mechanical agitator system for the Keck planet finder spectrograph
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用于凯克行星探测器摄谱仪的光纤双扰频器和机械搅拌器系统
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
A. Howard
中科院分区：
文献类型：
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作者：
M. Sirk;E. Wishnow;Marie Weisfeiler;E. Jhoti;J. Curtis;Yuzo Ishikawa;D. Finstad;Timothy J. O'Hanlon;Steven R. Gibson;J. Edelstein;S. Halverson;Arpita Roy;A. Howard
我们提出了一个双扰频器和光纤搅拌器系统的凯克行星射电光谱仪（KPF）的设计和测试结果。用于模态噪声抑制的机械搅拌器由两个线性级构成，其中纤维安装在“W”曲线中。当以不同的速率来回驱动时，载物台改变光纤弯曲的位置，从而改变通过光纤传播的模式。由模态噪声引起的近场时间质心偏移被搅拌器减少了100倍，而中间范围的空间频率在近场中减少了1000倍的功率，在远场中减少了1000倍的功率。该扰频系统包括两个八角形光纤和一个扰频器，该扰频器由两个相距约20 cm的相同胶合透镜组成，该透镜交换光纤的光学近场和远场。加扰器在近场中示出> 16，000的加扰增益，并且在远场中示出> 40，000的加扰增益。测得的吞吐量效率的99.3%的预期最大值表明，扰频引起的焦比退化（FRD）是最小的。扰频器还用作进入容纳光谱仪的真空室的馈通件，从而消除了对光纤施加应力以及在该接口处引入FRD的担忧。我们的照明稳定系统，包括两个八角形光纤，一个双透镜扰频器，和一个机械搅拌器，产生非常均匀的光纤输出在近场和远场。当与凯克行星射电光谱仪耦合时，该系统提供对应于0.30 m s−1速度的照明稳定性。
We present the design and test results of a double-scrambler and fiber agitator system for the Keck Planet Finder (KPF) spectrograph. The mechanical agitator for modal noise suppression is constructed from two linear stages with the fibers mounted in a “W” curve. When driven back-and-forth at different rates, the stages change the position of the fiber curves, and hence vary the modes propagating through the fiber. Near-field temporal centroid shifts caused by modal-noise are reduced by a factor of 100 by the agitator, while mid-range spatial frequencies have reduced power by a factor of ∼300 in the near-field, and ∼1000 in the far-field. The scrambling system incorporates two octagonal fibers, and a scrambler consisting of two identical cemented lenses ∼20 cm apart, which exchanges the optical near- and far-fields of the fibers. The scrambler shows scrambling gains >16,000 in the near-field, and >40,000 in the far-field. The measured throughput efficiency of 99.3% of the expected maximum demonstrates that scrambler-induced focal ratio degradation (FRD) is minimal. The scrambler also serves as the feed-through into the vacuum chamber where the spectrograph is housed, thereby removing concerns about stressing the fibers, and introducing FRD, at this interface. Our illumination stabilization system, consisting of two octagonal fibers, a two lens scrambler, and a mechanical agitator, produces very homogeneous fiber output in both the near and far-fields. When coupled to the Keck Planet Finder spectrograph, this system provides illumination stability corresponding to a velocity of 0.30 m s−1 .
DOI：
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发表时间：
2016-10
期刊：
arXiv: Instrumentation and Methods for Astrophysics
影响因子：
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作者：
Desi Collaboration Amir Aghamousa;J. Aguilar;S. Ahlen;S. Alam;L. Allen;C. Prieto;J. Annis;S. Bailey-S
通讯作者：
Desi Collaboration Amir Aghamousa;J. Aguilar;S. Ahlen;S. Alam;L. Allen;C. Prieto;J. Annis;S. Bailey-S