Shaolong Zhong

Wavelength-Selective Switch Based on a Polarization-Independent Transmission Grating and a High Fill-Factor Micromirror Array

This letter presents a wavelength-selective switch (WSS) based on a polarization-independent transmission grating and a high fill-factor micromirror array. The WSS does not require additional polarization management devices and successfully achieves a low polarization-dependent loss (PDL). A 1 × 4 port WSS has been successfully demonstrated. The maximum driving voltage is about 155 V and an applied overvoltage also illustrates the good reliability of WSS. The test results show that the PDL is less than 0.4 dB. The measured fiber-to-fiber insertion loss (IL) is in range from about 6 to 7 dB and the switching time is about 530 μs .

A thermal tunable bulk-micromachined optical filter

This paper presents a novel thermal tunable bulk-micromachined optical filter. The device has been achieved based on a Fabry-Perot interferometer employing a bulk silicon cavity and high-reflectivity coating (HRC). A dense boron doped silicon resistor has been used as the heater and the cantilever structure has been designed to provide a good thermal isolation. The tunable optical filter has been successfully fabricated using bulk micromachining technology. Tunability is realized by changing the refractive index of the bulk silicon cavity through heating resistor. The maximum wavelength tuning is about 17 nm with driving voltage less than 14 V. The filter linewidth was achieved a value of 0.29 nm and the Free Spectral Range (FSR) was 21.9 nm. The heating and cooling responding times are less than 50 ms.

Optical fiber accelerometer based on MEMS torsional micromirror

A novel structure of optical fiber accelerometer based on MEMS torsional micro-mirror is introduced, including MEMS torsional micro-mirror and optical signal detection. The micro-mirror is a non-symmetric one, which means that the torsional bar supporting the micro-mirror is not located in the axis where the center of the micro-mirror locates. The optical signal detection is composed of PIN diode and dual fiber collimator, which is very sensitive to the coupling angle between the input fiber and output fiber. The detection principle is that acceleration is first transformed into torsional angle of the micro-mirror, then, optical insertion loss of the dual fiber collimator caused by the angle can be received by PIN. So under the flow of acceleration to torsional angle to optical signal attenuation to optical power detection, the acceleration is detected. The theory about sensing and optical signal detect of the device are discussed in this paper. The sensitive structure parameters and performance parameters are calculated by MATLAB. To simulate the static and modal analysis, the finite element analysis, ANSYS, is employed. Based on the above calculation, several optimization methods and the final structure parameters are given. The micro-mirror is completed by using silicon-glass bonding and deep reactive ion etching (DRIE). In the experiment, the acceleration is simulated by electrostatic force and the test results show that the static acceleration detection agrees with the theory analysis very well.

Fabrication of high fill-factor micro-mirror array with multi-terraced-plate structure

In order to obtain a micro-mirror array with large torsional angles and large sizes under limited driving voltages,a novel micro-mirror array with a multi-terraced-plate structure was proposed and demonstrated based on the Micro-optoelectro mechanical System(MOEMS).The different characteristics of the electrostatic driver between multi-terraced-plate structure and parallel-plate structure were analyzed.The key fabrication process for the multi-terraced-plate structure was researched and a bulk micro-mechanical technology was used to fabricate a micro-mirror array with the multiterraced-plate structure.The obtained micro-mirror array contaning 52 micromirrors has the size in 600 μm by 200 μm,and a high fill-factor in excess of 97%.The test results show that the micro-mirror array achieves a maximum torsional angle about 1.1° under a driving voltage of 164 V,and the multi-terraced-plate structure greatly reduces the driving voltage as compared with the traditional parallel-plate structure.