Abstract: A system and method for resolving polarization mode dispersion (PMD) in a span of optical fiber is described. The method involves three main stages: (1) launch two co-polarized optical signals to generate respective four-wave mixing product fields at the Stokes wavelength &lgr;S or the anti-Stokes wavelength &lgr;A sequentially in each part of the fiber to calculate chromatic dispersion; (2) repeatedly launch two optical signals at various states of polarization (SOP) using methods of stage (1) to calculate overall dispersion (i.e., a combination of chromatic dispersion and PMD); and (3) resolve from the overall dispersion calculated at stage (2) the PMD based on the known chromatic dispersion calculated at stage (1). In an ideal case, the PMD can be calculated from two separate measurements at different co-polarized states of polarization, where group velocity is calculated from a measured dispersion map, as a function of wavelength, at the SOPs and the difference is calculated to resolve PMD.

Abstract: An optical circuit has a loop mirror coupled to a 3-dB coupler, with a chirped fiber Bragg grating coupled in the mirror loop. When a beam of light from a broadband light source is launched into the circuit, the circuit functions as a tunable notch filter or as a bandpass filter depending on which output port of the coupler is used to monitor the response. An interference fringe pattern generated in the response of the circuit enables to determine dispersion of the chirped Bragg grating.