Simple technique for integrating compact silicon devices within optical fibers

• Published in: Optics letters Vol. 39; no. 4; p. 861
• Main Authors: Micco, A, Ricciardi, A, Quero, G, Crescitelli, A, Bock, W J, Cusano, A
• Format: Journal Article
• Language: English
• Published: United States 15.02.2014
• ISSN: 1539-4794
• DOI: 10.1364/OL.39.000861

In this work, we present a simple fabrication process enabling the integration of a subwavelength amorphous silicon layer inside optical fibers by means of the arc discharge technique. To assess our method, we have fabricated a compact in-line Fabry-Perot interferometer consisting of a thin (<1  μm) a-Si:H layer completely embedded within a standard single-mode optical fiber. The device exhibits low loss (1.3 dB) and high interference fringe visibility (~80%) both in reflection and transmission, due to the high refractive index contrast between silica and a-Si:H. A high linear temperature sensitivity up to 106  pm/°C is demonstrated in the range 120°C-400°C. The proposed interferometer is attractive for point monitoring applications as well as for ultrahigh-temperature sensing in harsh environments.