Open AccessSensing and transmission characteristics of a rocking filter fabricated in a side-hole fiber with zero group birefringence
Author(s) -
Alicja Anuszkiewicz,
Tadeusz Martynkien,
Paweł Mergo,
Mariusz Makara,
Wacław Urbańczyk
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.012657
Subject(s) - birefringence , optics , materials science , beat (acoustics) , polarization maintaining optical fiber , dispersion shifted fiber , optical fiber , photonic crystal fiber , wavelength , graded index fiber , physics , fiber optic sensor
We report on sensing and transmission characteristics of rocking filters fabricated in a silica side-hole fiber with group birefringence changing its sign at certain wavelength (λ(G = 0)), which corresponds to parabolic-like spectral dependence of beat length. Unusual birefringence dispersion of the side-hole fiber is induced by an elliptical germanium doped core located in a narrow glass bridge between two holes. Rocking filters fabricated in such a fiber have two resonances of the same order located on both sides of λ(G = 0). The sensitivity of both resonances has an opposite sign, which makes it possible to double the response of the rocking filter by applying the differential interrogation scheme. We demonstrate that in this way a pressure sensitivity of the rocking filter can be enlarged to 132 nm/MPa. We also show that by fabricating the rocking filter with a period close to maximum beat length a coupling between polarization modes can be obtained in a broad band reaching 240 nm.