Study On Optical Coupling Performance Of Inclined Optical Fiber And Photodetector

In the testing of photodetector chips,optical signals are usually input by vertical coupling of planar optical fibers.Since the optical fiber and the photosensitive surface of the detector are coupled out of plane,the high-frequency probe pricks the detector and the microscope observation are all in the vertical direction of the photodetector chip,the spatial overlap of the relative positional relationship among the four is high,which will have a certain impact on the test.The tedious position adjustment and fixture stage selection to meet the experimental requirements will consume a lot of test time and reduce the test efficiency.The horizontal coupling between the inclined optical fiber and the detector can effectively avoid the problems in the vertical coupling process,reduce the time for building the test experimental system and improve the test efficiency.This paper mainly studies the optical coupling between the inclined optical fiber and the device,mainly the coupling with the photodetector chip.The simulation results are verified by the specific test results,and the micro-distance measurement method of the space optical path is also studied by using the fiber Fabry-Perot cavity effect.1.Firstly,Lumerical is used to simulate the output light field of inclined optical fiber.The effects of coupling errors such as longitudinal offset,transverse offset and fiber angle torsion on coupling efficiency are simulated respectively.The effects of wide spectrum light source and inclined optical fiber with different cutting angles on output light field are also studied.2.Design the coupling experiment system of inclined optical fiber and detector.According to the simulation results,test it through experiments.3.Set up an optical fiber micro-distance measuring system,respectively using two planar optical fiber end faces,inclined optical fiber end faces and detector photosensitive faces as optical fiber Fabry-Perot cavities,using spectrometer and tunable laser to scan spectra,and obtaining theoretical cavity length value through spectrum analysis and calculation;At the same time,the actual cavity length measured by side high power microscope is compared with itFig.58 pictures,7 tables and 58 references.