Research and fabrication of multi-channel interference cut-off filter for 45° tilt application
Development of optical fiber communication puts forward new requirements of thin film filters in communication devices.According to the design specifications of multi-channel interference cut-off filter for 45° tilt application,Nb2 O5 and SiO2 are selected as high and low refractive index materials to design irregular,so that it can reduce the influence of polarization effect.Combined with the characteristics of the APS1104 type coating machine,layers sensitivity of the formula and the simulation monitoring curve during thin film growth process are analyzed to judge the producibility of the designed thin-film.Then,the filter is successfully deposited by adopting direct optical monitoring mode and selecting appropriate deposition process.The test results show that under the condition of 45° tilt application,the maximum insertion loss of 1255~1365 nm and 1 475~1 502 nm double passbands is 0.199dB,1547~1565nm is the reflection band,and the passband isolation is17.3dB,which meets the application requirements of the system.