A new method for measuring time-resolved frequency chirp of high bit rate sources

A new method for measuring time-resolved frequency chirp of a modulated light source at high bit rate is presented. This method uses a Mach-Zehnder interferometer as an optical frequency discriminator. No approximation is made for measuring the intensity and the phase of the sourceʹs optical field. This method allows to perform a precise measurement of the frequency chirp and the (alpha) parameter of a modulated light source at rates above 10 Gb/s. Experimental results demonstrate the use of this technique for measuring the frequency chirp and the (alpha) parameter of a directly modulated distributed-feedback laser at 20 Gb/s.