The Structure Design And Application Analysis Of Microring Resonator With U-bend Waveguide

With the development of the application of nano-materials and the technique of micromachining, the optical waveguide device gradually advances toward microminiaturization, integration and large-scale processing in optical communication field. Just like the large scale integrated circuit on the chip, the development direction of optical system is integrating many kinds of optical elements into an on-chip system to realize many different functions. Because of the nano-size and the remarkable filter effect, the microring resonator is not only suit for large scale integration, but also can realize several different functions including filter, register, laser, wavelength division multiplexer, optical switch, modulator, wavelength converter, logic gate, sensor and so on. Thus, microring resonator is becoming a hot research point in integrated optical system recently.This dissertation start from ordinary single mciroring resonator.Then we add a piece of U-bend feedback waveguide and discuss several new structures and their applications, Meanwhile we make sensing-modulating device and switch-logic device as their potential application direction,using U-bend waveguide to optimize the filter effect of microring resonator itself. At last, we also designed microring switch, logic gates and sensors with U-bend waveguide. Summarising the whole works, including:First of all, we studied the basic theory of microring resonator, designed several microring filter structures and built their math model by coupling mode theory and transmission matrix. Through the theoritical simulation we found that we can optimize the filter effects by adding U-bend waveguide and choosing proper parameters of microring, such as expanding the free spectral range, increasing the quality factor and extinction ratio. The enhancement of these filter effect can boost the improvement of photonic device which is based on filter function of microring. Besides,we tried to fabricate a microring with U-bend waveguide by photolithography technique and finished the photolithography process part so far.Secondly, we applied the designed microring resonator into optical switching field, use single-pole double-throw switch and polymer opti-electrical modulating unit to realize three on-off state.The new designed optical switch also improved the response speed thoerily. Besides, we designed two multiple functional microring logic gate with U-bend feedback waveguide.By choosing different input port and output port, it can realize several logic operation including AND, NAND,OR,NOR,NOR and XNOR.At last, based on the structure of microring resonator with U-bend feedback waveguide, we designed a double chamber gas sensor, which can measure the gas concentration in two chambers at the same time on same output spectrum, greatly saved the consumption on time and space.In the sensor, we use Zn O nano-crystals dying on the top of waveguide as cover layer and sensing unit, and discussed the two different absorption mechanism in different and its different sensitivity curves in sensing process.