Research On Waveguide Sensor Of Cascaded Two Ring Resonators Based On Polymer

Sensing technology as one of the three pillars of the information industry, penetrates into our lives deeply and has a vital impact on our lives with the development and penetration of the Internet technology. However, many of the traditional sensor cannot meet people’s all sorts of new demand. Therefore, it is more and more urgent to improve the sensitivity of the sensor, study the new sensor technology, and develop a sensor which has high sensitivity and can be integrated easily.Due to the using of the resonant cavity structure, the optical biochemical sensor based on the ring resonator has high quality factor, which is conducive to the realization of high sensitivity detection. The introduction of the resonant structure increases the interaction between the light and the subject matter. Therefore, it is less used in the treatment of the sample. Due to a series of advantages based on ring resonator, it is very important to carry out related research work. In view of this, this dissertation mainly studies a new type of polymer waveguide biosensor which is realized by cascading two ring resonators. Comparing with the traditional only one ring, the transmission spectrum of the proposed two ring resonators is enlarged by the cursor effect, which increases the sensitivity. Taking the detection of glucose solution concentration as an example, the sensing characteristics of the sensor were tested and analyzed. The main work of this dissertation is as following:Firstly, according to the technical level can be achieved in our lab and the refractive index parameters, we select polymer named benzocyclobutene(BCB) as the waveguide material. According to the characteristic parameters of BCB, we investigate the single mode waveguide and double-mode waveguide of cascade ring resonator by Marcatili method.Secondly, the basic structure of the waveguide ring resonator is introduced, and the output of the resonator is analyzed by transfer matrix method, the relationship between the input and output is obtained. The output spectrum of the cascaded double ring resonators and the principle of the cascade ring which has a higher sensitivity compared to single ring are analyzed.Thirdly, a series of the production process of polymer waveguides, such as ICP etching, magnetron sputtering, lithography and so on, are studied deeply. By these production process, we successfully fabricated a sample of polymer optical waveguide cascaded ring resonator which has small surface roughness and better sidewall verticality.Fourthly, by setting up a high-precision optical test platform, the result of transmission characteristics with the fabricated fixed cladding optical waveguide cascade ring resonator have a wavelength isolation of 10 dB. The sensing properties were tested with different concentration of glucose solution, and the expected target was achieved. The sensing properties were tested with different refractive index of index-matching fluid, and the expected target was achieved.