High-Birefringent Fiber Loop Mirror Sensors With an Output Port Probe

Two new configurations of high-birefringent fiber loop mirror with an output port probe are proposed. The two configurations used two couplers spliced between them with unbalanced arms and one output port is used as the probe sensor. The difference between them is that the section length of high-birefringent fiber is located between the two couplers (first new configuration) or spliced in the output port probe (second new configuration). The second new configuration presents great advantage, especially for remote sensing using only one fiber to the sensing head. The two new configurations were compared with the conventional high-birefringent fiber loop mirror when strain is applied and showed similar sensitivities. The first new configuration is studied as an optical refractometer.