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arXiv · 2508.09854

Temperature-compensating package for OH line filters for astronomy: II. manufacture, assembly, and performance study

Xijie Luo·Carlos E. Rodriguez Alvarez·Aashia Rahman·Azlizan A. Soemitro·Hakan Önel·Jens Paschke·Svend-Marian Bauer·Kalaga Madhav·Wilbert Bittner·Martin M. Roth
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Abstract

Multi-channel aperiodic fiber Bragg grating (FBG) based hydroxyl (OH) line filters have attracted significant interest in ground-based near-infrared (NIR) astronomical observations. In this paper, we present the performance of a new self-compensating enclosure for the filters, that can be used in non-temperature-controlled environments. Our prototype encloses a 110 mm long single-mode photosensitive optical fiber with three 10 mm filter gratings. A fourth grating was used as a reference outside the package to measure the uncompensated wavelength shift. The prototype was tested over three thermal cycles, and showed a maximum wavelength deviation of 12 pm, a wavelength drift of only 0.37 pm/$^{\circ}$C, over the temperature range of -17$^{\circ}$C to 15$^{\circ}$C. The athermalization factor, i.e., the ratio of the maximum wavelength shift of the compensated grating to the uncompensated reference filter grating was $\frac{1}{22}$. The results demonstrate the capability of the prototype for stabilizing multi-channel long-length FBGs or chirped FBGs, particularly for astronomical applications that require sub-picometer stability.

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Xijie Luo, Carlos E. Rodriguez Alvarez, Aashia Rahman, Azlizan A. Soemitro, Hakan Önel, Jens Paschke, Svend-Marian Bauer, Kalaga Madhav, Wilbert Bittner, Martin M. Roth. 2025-08-13. Temperature-compensating package for OH line filters for astronomy: II. manufacture, assembly, and performance study. https://doi.org/10.1364/oe.560633

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