Frequency-derived remote measurement of birefringence in polarization-maintaining fiber by using the optical Kerr effect

A technique to measure remotely the birefringence of polarization-maintaining fiber is described. The method uses a pump-and-probe scheme that employs the optical Kerr effect together with a small wavelength difference between the sources to allow a measurable derived frequency to be generated. The frequency depends on the birefringence of the fiber and the source wavelength offset. This latter feature provides a tunable frequency and hence an extra degree of freedom in the system design.