Micro-channels are very important in bio-medical and cooler research. Although many research have been conducted with micro-channels, few results have been contributed to discuss the properties of fluids inside a micro-channel. For example, the thermal distribution of the fluid in a micro-channel is only simulated with numerical analysis approach. In our research, we aim to design a device that can measure real thermal data within a micro-channel. We first applied excimer laser lithography on a PMMA substrate to fabricate a micro-channel with 20 mm length, 200£gm width and 200£gm depth. Micro-heater and micro-thermal sensor is than fabricated by sputtering pt thin-thim with PVD process on a glass substrate. Finally, these devices were assembled with UV-curing and than applied for further testing. According to our experiment, lift-off process cannot be easily applied to fabricate micro-heater and micro-thermal sensor since the architecture of these devices were fragile in metal line sidewalls. Wet-lithography is than used to conquer this problem. Our primary test on this micro-thermal sensor shows that its resistance varies with thermal changes. Such mechanism can be applied to measuring thermal field in a micro-channel.

Single-pass frequency conversion by a nonlinear optical crystal is an attractive method to generate coherent radiation in various spectral domains from ultraviolet to mid-infrared. Wavelength converters based on quasi-phase matched (QPM) periodically poled lithium niobate (PPLN) have proved to be important wavelength conversion devices for many useful applications. This thesis develops a novel integration design for temperature controlling and temperature wavelength tuning of a QPM-PPLN waveguide wavelength converter. A Cr/Pt/Au thin film alloy layer is deposited on a PPLN device with a polymer buffer layer to work as a micro-heater and a temperature sensor at the same time. The temperature of the device can be tailored by applying current to the micro-heater layer, which changes the effective period of the QPM grating and thus the QPM wavelength through the thermal optical effect (TOE). The device's temperature can be monitored by measuring the resistance change of the alloy layer. Micro-heater design and mode profile simulation are involved in the thesis. The entire device fabrication process is introduced. Both electrical and optical features of the device are characterized and discussed. In contrast to the conventional temperature tuning method based on a bulky oven, the proposed design has some excellent characteristics such as compact package size and low power consumption. / Thesis / Master of Applied Science (MASc)

In this research a state-of-the-art micro-thermal conductivity detector is developed based on MEMS technology. Its efficient design include a miniaturized 100×2 µm bridge from doped polysilicon, suspended 10 µm away from the single crystalline silicon substrate through a thermally grown silicon dioxide sacrificial layer. The microbridge is covered by 200 nm silicon nitride layer to provide more life time. Analytical models were developed that describe the relationship between the sensor response and ambient gas material properties. To obtain local temperature distribution and accurate predictions of the sensor response, a computational three dimensional simulation based on real geometry and minimal simplifications was prepared. It was able to handle steady-state and transient state, include multiple physics such as flow, heat transfer, electrical current and thermal stresses. Two new methods of measurement for micro TCD were developed; a time resolved method based on transient response of the detector to a step current pulse was introduced that correlates time constant of the response to the concentration of gas mixture. The other method is based on AC excitation of the micro detector; the amplitude and phase of the third harmonic of the resulting output signal is related to gas composition. Finally, the developed micro-sensor was packaged and tested in a GC system and was compared against conventional and complex FID for the detection of a mixture of VOCs. Moreover compact electronics and telemetry modules were developed that allow for highly portable applications including microGC utilization in the field.