The optical Kerr effect in coiled high-birefringent fibers was measured based on a double-beam polarimetric method. A <i>Q</i>-switched Nd:YAG laser, operating at 1.064 μm (FWHM of 80 ns at 1 kHz), was used as the pump beam and a cw 0.633-μm He–Ne laser was used as the probe beam with its polarization fixed at 45° with respect to the birefringent axis whereas orientation of the linearly polarized pump light varied. The phase shifts induced by an intense pump beam in a short bow-tie high-birefringent fiber were determined for different fiber lengths coiled into 15- and 30-cm-diameter drums. It was found that the induced phase shift changes drastically with the state of polarization of the pump light. A strong dependence of the phase shift on orientations of linear pump polarization is attributed to differential losses of eigenmodes peculiar to birefringent axes. Therefore, optical Kerr coefficients remain unchanged regardless of the dependence of the nonlinear response of the coiled high-birefringent fibers on pump polarization.
© 1998 Optical Society of America
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(120.5410) Instrumentation, measurement, and metrology : Polarimetry
(190.3270) Nonlinear optics : Kerr effect
(230.5440) Optical devices : Polarization-selective devices
Masaaki Imai, Hiroaki Ishikawa, Yasuhito Tsuji, and Yoh Imai, "Optical Kerr coefficient measurement in coiled high-birefringent fibers," Appl. Opt. 37, 1010-1015 (1998)