Linearly Swept Tunable Laser Source with Closed-Loop Control of Drive Waveform

A method for a linearly swept tunable laser source with a simple configuration is proposed. The principle of the method is based on the fact that the interval of the transmission peaks of a fixed etalon can be used as a stable reference. The reference provided by the fixed etalon is used to deform the drive signal waveform for linear optical-frequency tuning. To verify the validity of the methodology, an optical system augmented with two fiber Bragg gratings, one fixed etalon, and a dedicated signal-processing circuit was built and experimentally tested, confirming that it works well for a linearly tuned tunable laser source. Moreover, the potential for extending the scope of the application of the proposed method is suggested and some ways to improve its performance are also discussed.