Abstract

We report on experimental characterization of butt-coupling between a quantum cascade laser operating around the wavelength of 4.5 μm and a silica hollow core anti-resonant fiber. The used fiber has a single ring of non-touching capillaries surrounding a 42.5 μm dimeter air core and a mid-infrared transmission window in the wavelength range of 2.8 to 4.7 μm. A lens-less butt-coupling interconnection is established and coupling efficiency of 22% is achieved with over 100 mW of power at the fiber output. Bending losses in this test-bed system are verified depending on radius with the loss remaining below 1 dB/m for 20 mm loops, while bend losses exceeding 10 dB/m are observed when the fiber is bent down to a 5-mm radius. The presented coupling dramatically improves the output beam quality of the quantum cascade laser with a measured NA = 0.45. The beam at the fiber output has a circular shape, measured M² = 1.04 and uniform numerical aperture of NA = 0.13. Together with the hollow core fiber geometry, the proposed system would be suitable for simple implementations of absorption spectroscopy of popular atmospheric agents, like N₂O.

Demonstration of mid-infrared gas sensing using an anti-resonant hollow core fiber and a quantum cascade laser

Michal Nikodem, Grzegorz Gomółka, Mariusz Klimczak, Dariusz Pysz, and Ryszard Buczyński
Opt. Express 27(25) 36350-36357 (2019)

Nested capillary anti-resonant silica fiber with mid-infrared transmission and low bending sensitivity at 4000  nm

Mariusz Klimczak, Dominik Dobrakowski, Amar Nath Ghosh, Grzegorz Stępniewski, Dariusz Pysz, Guillaume Huss, Thibaut Sylvestre, and Ryszard Buczyński
Opt. Lett. 44(17) 4395-4398 (2019)

Bending loss characterization in nodeless hollow-core anti-resonant fiber

Shou-Fei Gao, Ying-Ying Wang, Xiao-Lu Liu, Wei Ding, and Pu Wang
Opt. Express 24(13) 14801-14811 (2016)

Single-ring hollow-core anti-resonant fiber with a record low loss (4.3 dB/km) for high-power laser delivery at 1 µm

Shuai Gu, Xin Wang, Haoqiang Jia, Zhenggang Lian, Xiang Shen, Yifan Mai, and Shuqin Lou
Opt. Lett. 47(22) 5925-5928 (2022)

Design and fabrication of a tellurite hollow-core anti-resonant fiber for mid-infrared applications

Jun Zhu, Shaohua Feng, Chengzhen Liu, Liyang Cai, Yantao Xu, Xusheng Xiao, and Haitao Guo
Opt. Express 32(8) 14067-14077 (2024)