| At present, the development of electron integrated circuit affected by heat production and quantum tunneling effect is restrained. Integrated photonics is expected to overcome this difficulty. Samuel Fuller the chief technology officer of ADI company points out that integrated photonics in hardware can provide a large number of Internet, which depicts a blueprint of the photonic integrated development. In 1969, S.E. Miller from the Bell Laboratories put forward the theory of "integrated optics ", hoping to replace the integrated circuit in processing information. However after more than 40 years research, the development of integrated devices has not achieved the desired results. The biggest problem in the development of photonic integrated is that the optical diffraction limitation crubs the size of the device, so it is difficult to improve the integration of photonic devices. In recent years, some achievements have been made in the research of integrated optics based on silicon and lithium niobate. These devices can be achieved because of the refractive index of silicon and lithium niobate, a very narrow linewidth waveguide can be a strong constraint on the light.Lithium niobate is named as "optical silicon" in the scientific community due to its excellent comprehensive performance, high nonlinear coefficient, large light passing range (0.42um～5.2um), strong piezoelectric effect, strong heat release electric effect, and so on, which make it can provide multiple dimensions of regulation, so it is more and more popular in research. In particular, the nonlinear effects can be used to generate a new frequency of light or amplify the energy of other frequencies. And its application in the photonic devices in the future is very optimistic. In contrast, the light passing range of silicon (1.1um～1.6um) is smaller, and it has no nonlinear effect. So its control dimension in optic is small and a lot of functions in the photonic devices could not be achieved with silicon. Therefore, we have reason to believe that the lithium niobate based photonic devices has better prospects in the future.In addition to the high binding dielectric waveguide, In recent years, the rapid development of the surface plasmon polariton (SPP) which developed rapidly in recent years also provides a new way for the photon integration. Surface plasmon polariton bounds on the interface between the metal and dielectric is an electromagnetic mode generated by the collective oscillations of free electrons, whose mode area is in sub-wavelength dimensions, which can break through the diffraction limit and improve the photonic integration. So far, the academic circles have made some progress in SPP based photonic switches, photonic logic gates, photonic modulators and so on. But there is an obstacle on the way from SPP to photonic devices, which is the propagation loss. The general propagation length of SPP is only hundred micron magnitude, which means the size of the devices loop is limited within the range. The loss problem of the SPP must be solved for the real application to photonic devices and photonic chip. Fortunately, lithium niobate has a strong second order nonlinear effect. We can compensate for the loss of SPP, and even to enlarge the energy of SPP by the optical parametric amplification process (OPA).Based on the nonlinear effect of lithium niobate, we focus on the nonlinear process of lithium niobate in the photonic devices, and compensate the propagation loss of SPP by optical parametric amplification in the hybrid waveguide system. And we combine with photolithography, proton exchange, reactive ion etching to etch lithium niobate in a large area. We can also etch lithium niobate by focused ion beam etching technology to fabricate finer waveguides. In combination with these two processing schemes, we can get fine lithium niobate device efficiently. In this paper, the performance of photonic devices based on lithium niobate is studied by simulation software to prepare for the future implementation of photonic devices. |
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