The spectral shift of 100 GHz DWDM narrow bandpass interference filter

The 100 GHz narrow band pass filter (NBP filter), the total number of the layers being 187, is deposited by electron gun with ion-assisted deposition (IAD). When we grind, polish and cut the filter to 1.4 mm/spl times/1.4 mm/spl times/1 mm chips, the stress release curves the chip surface, and shifts the central wavelength of the NBP filter spectrum about-0.9 nm. The spectral shift can also be simulated by optical thin film program.