Abstract: A method and a system for interrogating an optical fiber includes a probe signal that has a first frequency comb at a first repetition rate (?f) injected into the optical fiber. A backscattering signal that includes the probe signal convolved with an impulse response of the optical fiber in reflection which is sensitive to at least one parameter being measured from the optical fiber is gathered. The backscattering signal is beaten with a local oscillator signal to generate a beating signal, the local oscillator signal including a second frequency comb at a second repetition rate that is offset from the first repetition rate (?f+?f) and being mutually coherent with the first frequency comb. The resulting beating signal is analysed to thereby determine the at least one parameter being measured from the optical fiber.

Abstract: The present invention relates to a system and method for measuring a wavelength-resolved state of polarization, for calculating differential group delay of an optical signal under analysis (1) by means of taking multiple measurements of the spectrum of the signal under analysis (1) with spectral filtering means (3) with an optical output the power of which depends on the polarization of the input. The polarization at the input of the spectral filtering means (3) is modified by means of a polarization transformer (2) which sequentially selects a plurality of output states of polarization. The spectral filtering means (3) can comprise a filter based on stimulated Brillouin scattering amplification (10) simultaneously combining wavelength discrimination and polarization discrimination.

Abstract: The present invention relates to a system and method for measuring a wavelength-resolved state of polarization, for calculating differential group delay of an optical signal under analysis (1) by means of taking multiple measurements of the spectrum of the signal under analysis (1) with spectral filtering means (3) with an optical output the power of which depends on the polarization of the input. The polarization at the input of the spectral filtering means (3) is modified by means of a polarization transformer (2) which sequentially selects a plurality of output states of polarization. The spectral filtering means (3) can comprise a filter based on stimulated Brillouin scattering amplification (10) simultaneously combining wavelength discrimination and polarization discrimination.