Silicon-Based Integrated Optic Pressure Sensor Using Intermodal Interference between TM-Like and TE-Like Modes

In this paper, a silicon-based integrated optic pressure sensor using an intermodal interference between the fundamental TM-like and TE-like modes is described. The sensor consists of a micromachined rectangular diaphragm and a straight polystyrene optical waveguide passing over the diaphragm. Its sensitivity is theoretically known to be strongly dependent on the position of the waveguide over the diaphragm. To experimentally investigate such dependence, we fabricated a sensor with a 1.2 mm ×10 mm ×20 μm diaphragm, over which waveguides were placed at 50 μm intervals. The measured phase sensitivity was 98 mrad/kPa for the waveguide nearest to the diaphragm edge. The measurement was also carried out for the other waveguides. As theoretically expected, the largest sensitivity was obtained for the waveguide nearest to the edge.     

Integrated Optic Pressure Sensor Using Intermodal Interference between Two Mutual Orthogonal Guided-Modes

We theoretically and experimentally investigated fundamental characteristics of an integrated optic pressure sensor using intermodal interference between the lowest-order TM-like and TE-like modes. The sensor consists of a rectangular diaphragm and a straight single-mode waveguide along an edge of the diaphragm. Its operation is based on a difference of phase retardations produced in the two guided modes through the photoelastic effect. The sensor was fabricated by bonding two glass substrates together: a Corning 0211 glass 300 μMm thick to form a waveguide and a thick substrate with a 10 mm × 10 mm square hole to define the diaphragm. The fabricated sensor was successfully tested using a He-Ne laser at 633 nm. The halfwave pressure was measured to be 77 kPa which is almost double the theoretical estimate.     

Theoretical Analysis of Silicon-Based Integrated-Optic Mach-Zehnder Pressure Sensors

Silicon-based Mach-Zehnder integrated-optic pressure sensors are investigated in this article. Several structures proposed in the literature are examined and performance parameters such as power leakage towards the Si substrate, radiation loss as a function of the Y-junction aperture angle, and halfwave pressure are analyzed. Modeling of the material deformation characteristics and refractive index change as a function of the applied pressure is carried out by using the finite-difference technique. The sensor optical characteristics and waveguiding properties are computed by using the finite-difference beam-propagation method (FD-BPM) and the extended effective index method (EEIM). Guidelines for performance optimization are proposed.     

基于偶联剂技术的光纤光栅压力传感实验研究

报道了利用偶联技术封装光纤光栅压力传感器的新方案.通过采用特殊聚合物材料将光纤光栅封装于金属管中,并采用偶联材料分别与聚合物和光纤以化学键偶联的工艺,解决了由于有机弹性体聚合物的弹性模量（1.2×105 N/m2）与光纤光栅的弹性模量(7×1010 N/m2)相差很大,在压强较大时易导致光纤光栅与聚合物材料之间的撕裂滑脱问题,改善了光纤光栅压力响应特性.封装后的光纤光栅压力的线性测量范围为0.04 MPa~0.6 MPa,压力响应灵敏度为－4.48 nm/MPa,与裸光栅压力响应灵敏度－0.003063 nm/MPa相比,增敏了1463倍.利用实验中所使用光谱仪0.05 nm的分辨率,压强测量准确度为±0.01 MPa,线性度为0.9978.