Nonlinear frequency conversion in a birefringent microstructured fiber tuned by externally applied hydrostatic pressure

Abstract

We studied vector frequency conversion in externally tuned microstructured fibers for applications as a novel, nonlinear fiber-optic sensor. We investigated both experimentally and numerically a possibility of shifting vector and scalar modulation instability gain bands by pressure-induced changes in the linear properties of a microstructured fiber. Our results show that polarization-dependent vector nonlinear processes sensitive to variation of fiber group velocity difference (group birefringence) exhibit a clear advantage for pressure-sensing applications compared with scalar nonlinear processes only sensitive to group velocity dispersion changes. Analytical predictions and numerical simulations confirm our measurement results.

Nonlinear polarization effects in optical fibers: polarization attraction and modulation instability [Invited]

“…pressure applied to the fiber, while the scalar MI sidebands are pressure independent. These results prove that frequency conversion by means of XPolM-MI in microstructured fibers is well suited for pressure-sensing applications [128].…”

“…Let us note that the coexistence of scalar and vector MI has been also observed in PCF with normal dispersion [129]. In particular, the impact of hydrostatic pressure on MI gain bands was studied [128]. Their experimental results show that scalar MI is insensitive to hydrostatic pressure, while the XPolM-MI strongly depends on pressure.…”

“…Among the various methods which were proposed so far, the shift of the pump wavelength [127] or pressure-induced changes in the linear properties of a PCF [128] seem to be the most promising.…”

Cross-phase-modulation-instability band gap in a birefringence-engineered photonic-crystal fiber

“…This feature points out its high sensitivity to fluctuations of fiber parameters, which has hampered its observation in nonperfectly uniform PCFs [10]. Nowadays, PCF properties can be precisely tailored and controlled during the drawing process, thus allowing researchers to benefit from XPMI sensitivity for applications as a nonlinear fiber-optic sensor [11]. Indeed, PCFs have become a suitable platform to study XPMI at any wavelength, since they also offer extremely high built-in birefringence by breaking the standard perfect sixfold symmetric core and cladding structure [5,12].…”

Nonlinear Label-Free Biosensing With High Sensitivity Using As₂S₃ Chalcogenide Tapered Fiber

“…Also, it remains to be determined whether the unavoidable fluctuations in the microstructure along the PCF length after the activation of the fiber with the biolayers would decrease the effective FWM gain too much for the FWM peak to be detected [20], [21]. Since the theoretical prediction reported in [19], the nonlinear FWM-based sensing scheme has now experimentally demonstrated for refractive index [22], strain [23], and pressure sensing [24].…”