Measuring dynamic chirp in DFB lasers using an all-fiber implementation

The temporal response of the optical frequency of a single- frequency DFB laser under direct current modulation is an important parameter for evaluating the performance of optical communication systems. Using an all-fiber Mach- Zehnder interferometer, serving as a frequency discriminator, this temporal response was measured with time resolution of 0.1nS and frequency resolution of 100MHz. While similar schemes were previously built for the same purpose, this is the first all-fiber implementation that uses no moving parts. This setup was successfully used to measure and model the adiabatic and thermal chirp of a 1.3 micrometers DFB laser. The same setup as also used for direct measurements of the laser's FM response.