title: High-birefringence fiber loop mirror sensor using a WDM fused fiber coupler.
abstract: An intensity-based highly birefringent (Hi-Bi) fiber loop mirror (FLM) sensor is proposed which uses a wavelength-division multiplexing (WDM) fiber coupler. The effect of integrating the WDM coupler in a FLM configuration is first studied. A section of Hi-Bi (bow-tie) fiber of length 0.26 m is then placed in the fiber loop, making the spectral response of the device simultaneously dependent on the Hi-Bi fiber section and WDM coupler characteristics. When strain is applied to the sensing head, the spectral signal is modulated in amplitude, in contrast with the conventional Hi-Bi FLM sensors in which there are wavelength shifts. The sensor was characterized in strain and a sensitivity of (-2.2±0.4)×10(-3) με(-1) for a range of 300 με was attained. The self-referenced character of the sensor is noted.
authors.affiliation: INESC Porto, Porto, Portugal.
authors.forename: D J
authors.initials: DJ
authors.lastname: Passos
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Marques
authors.forename: Orlando
authors.initials: O
authors.lastname: Frazão