半导体激光器与光纤光栅对接耦合研究

半导体激光器管芯与光纤光栅的对接耦合对光纤光栅外腔激光器的特性起到关键作用。利用散射矩阵分析了激光器管芯与光纤光栅外腔的对接耦合，发现对接的距离以及对接的耦合效率决定了光纤光栅外腔激光器的性能。在强反馈情况下,激射波长在光纤光栅外腔有效反射率决定的布喇格波长内随对接耦合距离周期性的变化,对弱反馈情况则有些不同。同时对比了两种情况的边模抑制比。该分析为实际制作器件提供了指导。     

Side-mode suppression and wavelength controltolerance for sampled grating based DWDM laser arrays

Sampled grating DBR (SGDBR) based laser arrays were demonstrated to be feasible for realizing monolithically integrated DWDM sources. In order to ease the post-fabrication wavelength control for SGDBR laser arrays, the influence of the sampling duty cycle and the difference of reflection peak spacing is analyzed and investigated experimentally for achieving the best side-mode suppression ratio (SMSR) of a SGDBR laser array. It is found that such type of laser arrays can have good tolerance on the mirror misalignment. We demonstrated arrays with uniform wavelength combs of 32 wavelengths in 0.8 nm wavelength spacing. Both high SMSR and accurate wavelength registration are achieved for all lasers in an array. We also demonstrated 16-wavelength laser arrays of 50 GHz spacing whose wavelengths are aligned to the ITU grid with single-electrode operation.     

Theoretical investigation into spectral characteristics of a semiconductor laser with dual-FBG external cavity

A new theoretical model of the dual-FBG external cavity based on the couple-mode theory has been proposed for controlling the output spectral characteristics of the semiconductor laser with dual-FBG external cavity. The output spectral characteristics have been studied through the analyses of the external cavity length, the FBG length and the fiber length between the two FBGs. The results reveal that the side mode suppression ratio (SMSR), the full wave at half maximum (FWHM), the longitudinal mode interval (LMI) and the stability of the central wavelength are mainly determined by the effective external transmissivity, the fiber length between the two FBGs and the external cavity length, respectively. Furthermore, the rising/falling tendencies of the SMSR and the FWHM are exactly opposite. There exist the maximum of the SMSR and the minimum of the FWHM in a semiconductor laser with dual-FBG external cavity. The increase of the fiber length between the two FBGs results in the exponential decrease of the LMI. The increase of the external cavity length leads to the better stability of the central wavelength.