| Abstract [eng] |
Optical fiber is a device with unique sensor technology features. It can be used not only for signal transmission, but also for measurements. Compared to electrical and bulky optical sensors fiber - optic sensors have definite advantages. These sensors are small, environmentally resistant, safe, highly sensitive and can measure many parameters. Many different OS sensors have been developed: fiber - optic gyroscopes, nonlinear scatter sensors, fiber - optic gratings, and interferometers. An example of fiber - optic sensor is Mach - Zehnder interferometer, which has attracted a great deal of interest due to its high sensitivity and high fringe visibility. This thesis describes the formation of MZI cavity using UV (206 nm) fs pulses. Firstly, the optimum ablation parameters were obtained experimentally to achieve the lowest surface roughness and the perpendicularity of the interferometer walls. Secondly, the best ablation algorithm has been chosen to avoid surface stresses that cause fiber breakage. Finally, the sensor was tested at different salt concentrations. Experimental results showed that at 62 % pulse overlap, structures with the lowest surface roughness Sa = 148 ± 12 nm and wall angle of 116 ° are formed. Applying the best ablation parameters, a MZI trench was attempted to be formed. Unfortunately, the scanned fiber optics broke due to the surface tensions caused by attaching it via connectors to the measuring devices. Finally, fractures were averted by forming structures that retained the cylindricality of the fiber. After the prototype of the 187 μm MZI cavity was formed, it was immersed in salt solutions of different concentrations, but the interference spectrum was not observed due to the potentially damaged core. More detailed research is needed to argue this hypothesis. |
