| The unprecedented demand for optical network capacity has fueled the development of optical swap optical switch and switch arrays.Lithium Niobate, as one of the substrates of making optical switch, has been studied extensively for its good electro-optic coefficient, ease of processing and proper cost for about several decades. Besides, the switch which is made of it is capable of changing its state extremely rapidly, typically in less than a nanosecond. Its development orient ion is low port switch array.A novel design of digital optical switch with lower crosstalk by employing S curve waveguide at the end of the Y branch is proposed after comparing different types of material, structure and switch effect. S curve waveguide here plays the role of variable optical attenuator (VOA). We could control the propagation channel of the device by exerting the synchronous voltage to the Y branch and S curve waveguide, resulting in lower crosstalk than the device without S curve waveguide.In order to explore the factors affecting the switch, we experimented the process and simulated different switch structures, and obtained the best technology parameter and structure parameter which are as follows: waveguide width: 6-7μm, titanium film thickness: 60nm, index change: 0.007, diffusion temperature: 1050℃, diffusion time: 9-10h; switch length: 27mm, the branch angle: 0.18°, side distance of electrode: 3.5μm. FDBPM is used to simulate the performance of the design, and it shows that the extinction ratio of VOA can exceed 20dB with the switch voltage of about 10V; the crosstalk of the switch is lower than -30dB, which is lower than the switch without VOA.We also explored the different technology process such as photolithograph, strip and grinding the facet of the substrate, obtained good technology parameters. But with the limitation of the time and the experiment condition, we just finished the waveguide and its test of light through the waveguide, the electrode will be coated in the next process. |
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