Wang Yuelin

Silicon-on-Insulator-Based Compact Optical Demultiplexer Employing Etched Diffraction Grating

A compact optical demultiplexer with etched diffraction grating (EDG) is designed and fabricated on a silicon-on-insulator (SOI) material. Several 90? turning mirrors are used to bend the waveguides, and the size of the EDG-based demultiplexer is minimized to only 16?1.7?mm2. The crosstalk is about -18?dB. The on-chip loss is about 18.2?dB, which is composed of about 16.9?dB excess loss and 1.3?dB diffraction loss. Measures to improve the performance are discussed.

Thermally excited micromechanical vacuum resonator

A micromechanical resonator is proposed and realized. It consists of a single-crystal silicon beam and two P-type silicon resistors. One resistor is used to excite the vibrating beam and the other to sense vibration of the beam. The dimensions of the resonator are about 4/spl times/2.5 mm/sup 2/, the resonant frequency is about 7.8 KHz, Q factor about 190 in air and above 2500 in vacuum degree of 7.5/spl times/10/sup -4/ Pa. The theory of thermal excitation is analyzed and the characteristics of the resonator are tested. We conclude that the resonator can be applied to vacuum measurement by the means of closed-loop resonating circuit. The design and realization of the circuit are described.

A study on etching profiles of sacrificial layers

Chemical etching of sacrificial layers is a widely used technique in surface micromachining. The causes of the triangle at the etch front are analyzed. The viewpoint that stress is the major factor of the triangles formation is put forward. Through a study of the mechanism of the effects of annealing on etch rate, several rules about different annealing conditions having different effects on the etch rate are advanced.

A NOVEL STRUCTURE OF ALL-OPTICAL TYPE SILICON MICRORESONATOR

A novel All-Optical type Silicon MicroResonator (AOSMR), with exciting and testing optical fibers is reported in this paper. It consists of a ridge optical waveguide and input and output optical fibers to pick up vibrations. The advantages include simplicity in structure and convenience in operation. Both theoretical analysis and experimental results showed that the new structure has large misalignment tolerance between the fiber and vibrator. The optical length of the fiber does not affect the output signal. In addition, the resonant frequency of the vibrator is independent of the internal stress of the silicon wafer.