A major obstacle preventing closer wavelength division multiplexing (WDM) channel spacing is the drift of emission wavelength with temperature variation. Therefore, with the development of dense WDM (DWDM) systems, lasers with narrow linewidth, high side mode suppressed ratio, low chirp, low cost, fast response, and stable dynamic single-mode operation are indispensable. In recent years, fiber-grating Fabry-Perot (FGFP) laser is emerging as an alternative light source for WDM systems. The emission wavelength of FGFP laser depends on the Bragg wavelength of fiber grating, thus independent of...