Microheater

About: Microheater is a research topic. Over the lifetime, 814 publications have been published within this topic receiving 12478 citations.

High-Q microresonators integrated with microheaters on a 3C-SiC-on-insulator platform.

Abstract: We demonstrate, to the best of our knowledge, the first thermally reconfigurable high-Q silicon carbide (SiC) microring resonators with integrated microheaters on a 3C-SiC-on-insulator platform. We extract a thermo-optic coefficient of around 2.67×10−5/K for 3C-SiC from wavelength shift of a resonator heated by a hot plate. Finally, we fabricate a 40-μm-radius microring resonator with intrinsic Q of 139,000 at infrared wavelengths (∼1550 nm) after integration with a NiCr microheater. By applying current through the microheater, a resonance shift of 30 pm/mW is achieved in the microring, corresponding to ∼50 mW per π phase shift. This platform offers an easy and reliable way for integration with electronic devices as well as great potential for diverse integrated optics applications.

Numerical Simulation of growth and collapse of a bubble induced by a pulsed microheater

Abstract: A three-dimensional numerical analysis of the growth and collapse of a bubble on a microheater is presented. SIMULENT code, which solves the full Navier-Stokes equations with surface tension effects, is used in these simulations. A volume of fluid (VOF) interface tracking algorithm is used to track the evolution of the free surface flow. A one-dimensional heat conduction model is used to consider the energy transfer between the bubble and the surrounding liquid, as well as the temperature distribution in the liquid layer. Details of the velocity and pressure distribution in the liquid during the growth and collapse of the vapor bubble are obtained. Numerical results for the growth and the collapse of the bubbles are compared with those of experiments under similar conditions. Comparisons show that the volume evolution of the vapor bubble is well predicted by the numerical model.

Compact Thermo-Optic Switch Based on Tapered W1 Photonic Crystal Waveguide

Abstract: A compact thermo-optic switch based on the cutoff effect of slow-light mode of a tapered W1 photonic crystal waveguide (PCW) is demonstrated with an integrated microheater. Due to the low-group-index taper, the coupling loss of the slow-light PCW is reduced, and a high switching extinction ratio (ER) is attained. Moreover, three types of microheaters are evaluated for the power consumptions, heating transfer efficiency, and temperature uniformities, and an optimized slab microheater is utilized. As a result, low switching power of 8.9 mW and high ER of 23.5 dB are achieved experimentally, while the length of W1 PCW is only 16.8 μm.

$\hbox{MnO}_{2}$ Nanowire Embedded Hydrogen Peroxide Monopropellant MEMS Thruster

Abstract: Feasibility of chemically synthesized MnO2 nanowire catalyst embedded silicon microelectromechanical systems (MEMS) H2O2 monopropellant microthruster has been demonstrated. Due to exothermic reaction process, sustenance of thrust generation does not require any heating of propellant thus minimizing electrical power requirement. The thruster device integrates inlet nozzle, microchannel, MnO2 nanowire embedded reaction chamber, in-plane exit nozzle and a microheater in the silicon layer. Nozzle configuration and catalyst bed was designed using simple analytical equations to achieve complete decomposition of H2 O2 and maximum thrust force by controlling the propellant flow. Simulation of hydrogen peroxide decomposition process was carried out to evaluate the thermo-chemical characteristics. The MnO2 nanowire has been obtained using a low-cost synthesis process and characterized using field emission scanning electron microscopy, Energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction studies. Thruster fabrication using micromachining process and its testing have been briefly described. The device is capable to produce 1 mN thrust and specific impulse of 180 s using 50 wt.% concentrated H2O2 of flow rate 1.25 mg/s with total ignition energy of 44 J required for preheating the catalyst bed. Detailed thrust measurement was carried out with propellant mass flow rate for different throat area of exit nozzle, and the results were interpreted with theoretical model.

Design, Fabrication, and Characterization of a High-Heating-Efficiency 3-D Microheater for Catalytic Gas Sensors

Abstract: In this paper, a novel 3-D microheater has been developed in order to improve the performance of catalytic gas sensors. The 3-D microheater consists of a platinum heater embedded in a concave-shaped membrane which was formed in twice wet-chemical anisotropic etching with photoresist-spray-coating-based liftoff process. Based on the 3-D microheater, a catalytic gas sensor with a paired detector and compensator was developed by sol-gel process, introducing γ-Al2O3-supported 15-wt % Pd as catalyst. Finite element method analysis results suggest that sensitivity of the catalytic gas sensor can be improved by loading more catalyst on the active area and concentrating more combustion heat inside the concave-shaped membrane. Test results indicate that a high heating efficiency has been achieved. Power per active area of the 3-D microheater is only half or less than that of current 2-D microheaters. Sensor response to methane shows that the sensitivity to 50% lower explosive limit CH4 was 12 mV/ % CH4.