Flexible Thermal Optical Switch Based On Norland Optical Adhesive

Flexibility is one of the common features of majority polymer materials.Polymer electronic paper, electronic skin and flexible display devices have become aresearch hotspot in recent years. If we want to get flexible integrated chips, we mustachieve signal sensing, control, processing and other functions on one chip. Opticalswitches are important components of the optical communication network and theyare key parts of “lab on a chip”. The research of flexible optical switch has greatsignificance to achieve flexible and portable devices and “lab on a chip” based on thinfilms.NOA (Norland Optical Adhesive) is a kind of UV-curable polymer materials. Ithas lower loss in communication band and good flexibility. Because of the aboveproperties, this paper has chosen the NOA to fabricate flexible thermo-opticalswitches. The characterization of NOA and the design and fabrication process ofdevices are discussed, and then we fabricate the flexible thermo-optical switchessuccessfully. The followings are the main work of this thesis:1、The UV-curing polymer series materials NOA is characterized though a seriesof methods. The optimum film formation conditions included rotating speed of4500r/min by a spin coater and exposure time for7minutes by a exposure box. The RMSof the film surface is1.18nm in the area of25μm×25μm. The refractive index ofNOA61and NOA88in the wavelength of1550nm is1.570and1.559which isshowed by the data of ellipsometer measurement. When the value of the bias power is200W and antenna power is100W, we can get the best Inductively Coupled Plasmaetching conditions.2、We fabricate ridge waveguide devices based on silicon and Mach-Zehnderthermo-optic switches by NOA. The fabrication process includes spin-coating,aluminum metallization, lithography, developing, and ICP etching. Then we test thedevices. The insertion loss of the2.2cm long ridge waveguide in the wavelength of1550nm is8.3dB. The extinction ratio of the Mach-Zehnder thermo-optic switch is 11dB, and driving power is85mW, and the rise time and fall time of thethermo-optic switch are1.085ms and489.5μs respectively.3、 We fabricate flexible inverted-ridge waveguide devices and flexibleMach-Zehnder thermo-optic switches by NOA. Firstly, we design and fabricate thenanoimprint lithography template with the polymer material SU8, and fabricate a2cmlong flexible inverted-ridge waveguide device by nanoimprint lithography. Then wechoose the dicing saw, ICP etching machine, femtosecond laser and excimer laser toprepare the end faces. After a series of experimentation, the best experimental result isfound by the excimer laser when the voltage is32kV and the frequency is15Hz. Theinsertion loss of the2cm long inverted-ridge waveguide in the wavelength of1550nm is14.3dB. Flexible electrode devices are fabricated and their performances arenot change too much when the devices bend. We test the electro-conductibility againafter two weeks, one month and three months to validate the durability of the devices.The results indicate that the rate of change of flexible electrode device is less than2%.At last, we fabricate flexible Mach-Zehnder thermo-optic switches. The extinctionratio of the Mach-Zehnder thermo-optic switch is11dB, and driving power is80mW,and the rise time and fall time of the device are1.987ms and2.712ms, respectively.