Spectral characteristics for a fiber grating external cavity laser

A numerical investigation has been carried out on the influence of the anti reflection (AR) coating of laser, the coupling efficiency of laser and fibe r (eta), and the reflectivity of fiber grating (R-g) on the side-mode suppr ession ratio (SMSR) of the fiber grating external cavity laser (FGECL). The FGECL was fabricated by the assembly of the multimode Fabry-Perot (FP) las er chip and fiber grating. The results showed that the FGECL with a lower A R coating, higher eta and R-g exhibited a better SMSR. A comparison of the SMSR dependence on the eta and R-g showed that SMSR increased more rapidly with increasing eta than SMSR for R-g. These spectral characteristic studie s of the SMSR dependence on the device parameters of the AR coating, eta, a nd R-g may provide useful device designs for the practical fabrication of a FGECL for use in dense wavelength division multiplexing (DWDM) application s.