Self-Enclosed All-Fiber In-Line Etalon

Abstract

An in-line fiber etalon, formed by a self-enclosed Fabry-Perot (F-P) cavity inside an optical fiber fabricated by using 157 nm laser micromachining, is first demonstrated. This etalon has almost perfect characteristics, such as excellent interferometric fringe visibility of up to ~30 dB, low thermal cross-sensitivity, great potential to realize mass-production with good reproducibility, low-cost, and super capability to operate in harsh environments, etc. It could be used as a precise wavelength reference or a practical strain sensor without any thermal compensation.