Active wavelength control in a single-frequency fiber laser via modulation of dynamic population grating

This paper demonstrates a technique for precise wavelength tuning in a single-longitudinal-mode (SLM) fiber laser by exploiting modulation in the reflectance spectrum of a dynamic population grating (DPG) to induce controlled mode hops. Implementing this technique to an SLM Erbium-doped fiber laser, we demonstrate a 1.4 nm wavelength tuning range with constant DPG modulation and the possibility to change the tuning pattern with an accuracy of about one free spectral range (∼10 MHz) by varying DPG modulation. These results establish a new way for controlling DPG-based tunable lasers, enhancing their potential for practical applications.