Widely Tunable Polarization Modulation Instability in D2O-Filled Microstructured Optical Fiber

Polarization modulation instability (PMI) is a nonlinear effect in which two pump photons with identical polarization propagating in a nonlinear medium give rise to two new photons of different frequency and orthogonal polarization with respect to the pump photons [1] . In this work, we report the experimental demonstration of broad spectral tuning of PMI generated in solid-core microstructured optical fibers (MOF) that were previously infiltrated with heavy water (D 2 O). MOFs were designed and fabricated with the appropriate dispersion characteristics to produce widely spaced PMI spectral bands when they were filled with D 2 O and pumped at 1064 nm. Heavy water was chosen due to suitable refractive index, large thermo-optic coefficient (~6.6×10 –5 K −1 ) and relatively low absorption in the near-IR. Tuning effect was achieved by exploiting the strong dependence of the PMI frequency shift on the fiber dispersion and birefringence [2] .