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Responses of microstructure optical fibers to strain and pressure

The phase/birefringence sensitivities of the fundamental mode of air-silica microstructure optical fibers to strain and pressure are investigated. Theoretical models are built for both hollow-core photonic bandgap fibers and solid-core highly non-linear photonic crystal fibers to study the effects of axial strain, lateral pressure, and acoustic pressure on the fiber length and the effective refractive indexes of the fundamental mode. Numerical simulation shows that the phase/birefringence sensitivity to pressure of a hollow-core photonic bandgap fiber depends strongly on the thickness of the outer solid-silica layer and the air-filling ratio of the microstructure inner-cladding, and the normalized phase sensitivity to acoustic pressure can be 35 dB higher than that of the conventional single mode fiber. Potential applications of the microstructure optical fibers for high sensitivity hydrophones and novel polarization controllers are discussed.