Optical narrow band filter without resonance's

This paper introduces an optical wave lter , which uses gratings at 45 or 135 inclined grating lines that avoid any resonances. Therefore, many more options to form the lter shape exist. In general, the lter design can be traced to that of transversal lters (nite impulse response lter , FIR lter). Such an integrated optical wave lter is characterized by steep lter slopes and a narrow pass band (less then 0 1nm) combined with a high stop band attenuation (more than 40dB) and a linear phase response in the pass band. Compared to conventional Bragg grating lters, the inclined grating line lters can have a atter pass band and steeper lter skirts related to the width of the pass band. In general, the lter' s realiza- tion is possible using any optical material. In view of the excellent optical properties the semiconductor material system InP/InGaAsP is used for manufacturing the lter .