Frequency stabilization of distributed-feedback laser by time measurement

We present a novel method of stabilizing a distributed-feedback laser. It's the first time to our knowledge that the timemeasurement technique is used in laser frequency stabilization. We obtain the laser frequency deviation information from the Fabry-Perot interferometer based on the pulse delay time. In contrast to traditional approaches, the laser can be stabilized in the quasi-continuous spectrum that the interferometer covering. Our method can obtain the error signal from a high signal to noise ratio (SNR) of the voltage signal and not limited by the frequency references. It also avoids many traditional problems, such as power insensitive, modulation, low-level signal, and finite frequency references. A relative frequency fluctuation less than 0.1 MHz is achieved and the root of an Allan variance is about 10-11 for an average time of 10 s.