Measurement of dispersion characteristics of two-mode birefringent optical fibers by spectral interferometric techniques

Abstract

We present the results of measurement of dispersion characteristics of two-mode highly birefringent (HB) fibers by three spectral interferometric techniques. First, a technique employing a tandem configuration of a Michelson interferometer and HB fiber under test is used for a broad spectral range measurement (e.g. 500-1300 nm) of the group modal birefringence for two spatial modes supported by the fiber. Second, a method of a lateral point-like force acting on the fiber and based on spectral interferometry is used for measuring the phase modal birefringence at one wavelength for the fundamental mode only. The measured value is combined with the dispersion of the group modal birefringence to obtain the phase modal birefringence over a broad wavelength range. Third, a spectral interferometric technique employing an unbalanced Mach-Zehnder interferometer with HB fiber in the test arm is used for measuring the wavelength dependence of the chromatic dispersion of the one of the polarization modes supported by the HB fiber over a broad wavelength range (e.g. 500-1400 nm). From this dependence and from the chromatic-dispersion difference, which is obtained from the measured group modal birefringence, the chromatic dispersion of the other polarization mode supported by the HB fiber is retrieved. We measured by these techniques dispersion characteristics of two HB fibers, including elliptical-core HB fiber and microstructured HB fiber.