Research On Novel Resonant Cavity And Its Application In Photodetectors

At present,the advancement of the Broadband Chinese strategy,the arrival of the era of 5G,the development of new applications such as the Internet,big data and cloud computing provide a new opportunity for the optical fiber communication.In optical communication systems,optical resonators can be used in many key components of optical communication systems such as lasers,photodetectors,optical modulators,optical switches,and optical routing.Therefore,the research on optical resonant cavity can actively promote the development of optical communication technology,which has important research value and practical application value,and is of great significance for the future development of optical communication and quantum communication.There are many kinds of optical resonators.Among them,the Fabry-Perot resonator has a simple structure and good performance,and is widely used in information optoelectronics and optical communication system devices.With the development of optoelectronic device size to miniaturization,optical microcavities with high quality factor and small mode volume have been widely studied and applied.In this paper,theoretical and experimental research work has been carried out around the new resonant cavity and its application to photodetectors.The main research contents and innovations of this thesis are as follows:1.A non-parallel cone-shaped resonator is proposed,which not only limits the beam in the direction of beam propagation,but also limits the beam in the lateral direction.Through the theory of wave optics,the eigenmode of the cavity is analyzed,and the resonant wavelength expression of the cavity is obtained.2.The cone-shaped resonator structure is optimized.In the range of the bottom angle of the study,a cone-shaped resonator structure with optimal structure was designed.When the bottom angle of the cone is 4.5°,the cavity length is 4508.7nm,and the bottom radius is 1410.6nm,the Q value of the cavity reaches 52748.6,which is 21%higher than the parallel cavity of the same size,and the mode volume is 2.49 ? m3.It is one-half the volume of the parallel resonator mode of the same size.In addition,the effect of the cone-top structure on the performance of the cone-top resonator is studied.The results show that the cone-top resonator is superior to the frustum-type resonator in single model.3.A RCE(Resonant Cavity Enhanced)photodetector is proposed,which is constructed by placing an absorption layer inside a cone-shaped resonator.Through theoretical calculations,it is found that when the thickness of the absorbing layer is 26.9nm,the bottom angle of the cone top mirror is 4.5 °,the cavity length is 4460nm,the device width is 2812.2nm,and the incident end mirror is 2.5 pairs of Si/SiO2 cone-shaped RCE light.The full width at half maximum of the quantum efficiency spectrum of the detector is 6.3 nm,and the full width at half maximum of the quantum efficiency spectrum of the FP-type RCE photodetector is 7 nm.Compared with the FP type RCE photodetector,the cone-top type RCE photodetector has a narrower quantum efficiency spectrum and a wider selection range of its absorption layer.4.A long strip-shaped resonant cavity inlay structure is prepared by using a reflow or anti-melting method.The prepared structure was characterized by using an electronic scanning microscope and a step meter,and a slope-like inlay structure with a strip width of 25 ?m and a height of 2.1 ?m was obtained.