Preparation technology of 1 550 nm notch filter

Notch filter has been widely applied in laser damage resistance, laser protection and optoelectronic countermeasure fields, how to improve the passband transmittance and lower the notch transmittance is one of the hot research topics. A Rugate notch filter with a central wavelength of 1 550 nm was designed at the band of 400 nm~2 500 nm, a sensitivity analysis was undertaken in which several reflectance spectra were generated as a function of variations in the refractive index profile. Moreover,the designed filter was deposited on a single surface K9 substrate by plasma enhanced chemical vapor deposition (PECVD) technology. The experimental filter has 3.62% transmittance at 1 550 nm and 88.54% average transmittance at the pass band.