Acta Optica Sinica, Volume. 31, Issue 10, 1023002(2011)
Finite-Difference Time-Domain Simulation of Polymer Self-Written Waveguide
SU-8 epoxy resin is a kind of polymer material of nonlinear optical properties. It is ultraviolet sensitive and its refractive index increases because of the photopolymerization. Finite-difference time-domain method is employed to simulate the process of photopolymerization, and the inner distribution of refractive index of SU-8 film is obtained. Both the process in the plane thin film and the thin film with a microlens are simulated. It is concluded that self-focusing effect which results from the refractive index change leads to the formation of self-written waveguide. The self-written waveguide consists of two continuous parts, one is cone and the other is cylinder. The length of the self-written waveguide increases with the time of exposure. Given the same exposure time, cone part in the SU-8 film with a microlens is more convergent than that without a microlens, and the length of the self-written waveguide in the SU-8 film with a microlens is longer than that without a microlens. The length of the self-written waveguide decreases with the increase of the ratio of the height to the basal diameter, given the same exposure time and a constant basal diameter of the microlens. The length of the self-written waveguide with the ratio 0.08 is 12.2% longer than that with the ratio 0.24, and the cone part with the ratio 0.08 is 19.2% longer than that with the ratio 0.24.
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Li Feng, Chen Sihai, Luo Huan, Gao Yiqing. Finite-Difference Time-Domain Simulation of Polymer Self-Written Waveguide[J]. Acta Optica Sinica, 2011, 31(10): 1023002
Category: Optical Devices
Received: May. 6, 2011
Accepted: --
Published Online: Sep. 27, 2011
The Author Email: Feng Li (lf_swnu@yahoo.com.cn)