Patent ID: 8280246
Filing Date: 2012-10-02
Classification: G01M,H04B

Abstract:
1. A method of measuring differential group delay in an optical fiber connection conveying an optical signal modulated by a digital signal at a given rate, said method including: phase modulating the optical signal by said digital signal at an entrance end of said optical fiber connection, rotating a polarization state of said modulated optical signal emerging from said optical fiber connection to provide a non delayed modulated optical signal, introducing an additional delay into said non delayed modulated optical signal to provide a delayed modulated optical signal, combining said delayed modulated optical signal and said non delayed modulated optical signal both polarized along two orthogonal axes into a resulting optical signal, selecting a polarization state in said resulting optical signal along substantially one of bisecting lines of said orthogonal axes into a linearly polarized signal, and determining the differential group delay in said optical fiber connection as a function of a characteristic of said polarized signal, said differential group delay being equal to the difference between the inverse of said given rate and said additional delay.