mirror and its sinc sine function mirror peak envelope of reflectivity peaks is clearly obvious a typical sampled grating includes a plurality of sampled grating portions separated from each other by portions with no grating the sampled grating can be defined by the length l b of each sampled grating portion and the sampling period u03bb see fig3 a modification of the sampling function f x to tailor the frequency response f u03bb of the peak envelope is well known to those skilled in the art in the case of the sg dbr to be produced with a phase mask the sampling function f x can only take the value of 0 1 or u2212 1 with u2212 1 indicating a phase reversal of the grating function thus sampling function value of u2212 1 indicates a sampled grating portion having a phase opposite that of another sampled grating portion having a value of 1 the phase mask technology for printing gratings allows the sampling function to take on a value of 1 0 and u2212 1 with a manufacturable process that can be used to create sampled grating phase masking is well known to those skilled in the art although this application is new this invention relates to using this added degree of freedom offered by current phase masking technology to tailor the spectrum of the sg dbr wavelength selective mirrors to improve the laser performance an embodiment of this invention can be as simple as adding a single anti phased i e having a phase opposite that of the sampled grating portions 402 a 402 b first grating burst portion 400 at the beginning of the first sampled grating portion 402 a of a plurality.