Sensors interferometers

Stamm Ch and Lukosz W 1994 Integrated optical difference Interferometer as biochemical sensor Sensors Aotuators B 18-19 183-7... 

Figure 13.55 shows the principle of a gas sensor based on an electrically tunable micromachined Fabry-Perot interferometer, and the shifting ol the pass band controlled by rhe tuning voltage. 

Inertial sensors are useful devices in both science and industry. Higher precision sensors could find practical scientific applications in the areas of general relativity (Chow et ah, 1985), geodesy and geology. Important applications of such devices occur also in the field of navigation, surveying and analysis of earth structures. Matter-wave interferometry has recently shown its potential to be an extremely sensitive probe for inertial forces (Clauser, 1988). First, neutron interferometers have been used to measure the Earth rotation (Colella et ah, 1975) and the acceleration due to gravity (Werner et ah, 1979) in the end of the seventies. In 1991, atom interference techniques have been used in... 

Inertial sensors based on atom interferometer basic principle... 

We present here a summary of recent work with light-pulse interferometer based inertial sensors. We first outline the general principles of operation of light-pulse interferometers. This atomic interferometer (Borde et al., 1992 Borde et al., 1989) uses two-photon velocity selective Raman transitions (Kasevich et al., 1991), to manipulate atoms while keeping them in long-lived ground states. 

Heideman R.G., H. Kooyman R. P., Greve J., Performance of a highly sensitive optical waveguide Mach-Zehnder interferometer immunosensor, Sensors and Actuators B 1993 10 209-217. 

Interferometric sensors frequently have also been applied to biosensor measurements. Thereby, the evanescent field technique (Mach-Zehnder interferometer) has been compared with other optical detection principles regarding information on layer structure and in case of biosensing30. The... 

Fabricius N., Gauglitz G. and Ingenhoff J., A gas sensor based on an Mach-Zehnder interferometer, Sensors Actuators B 1992 7 672-676. 

Drapp B., Piehler J., Brecht A.. Gauglitz G., Luff B.J., Wilkinson J.S., Ingenhoff J., Integrated optical Mach-Zehnder interferometers as simazine immunoprobes, Sensors Actuators B 1997 39 277-282. 

Ymeti A., Kanger J.S., Greve J., Lambeck P.V., Wijn R., Heideman R.G., Realisation of a multichannel integrated Young interferometer chemical sensor., Appl. Opt 2003 42 5649-5660. 

Heideman R.G. and Lambeck P.V., Remote opto-chemical sensing with extreme sensitivity design, fabrication and performance of a pigtailed integrated optical phase-modulated Mach-Zehnder interferometer system, Sensors and Actuators B 1999 61 100-127. 

The beams are backreflected by the cube corner prisms which are fixed, respectively, on the sample and on the sample holder. Since the cube corner prisms are able to make reflected beam exactly parallel to incident beam, this interferometer is tilt independent. The reflected beams get back to the beam splitter through the same path, but shifted by about 2 mm in the vertical direction. The beam splitter lets a part of the two beams go towards the photodiode sensor and lets the other part of beams reach the laser source (off axis, therefore giving no feedback effect). 

Xiao, G. Z. Adnet, A. Zhang, Z. Sun, F. G. Grover, C. P., Monitoring changes in the refractive index of gases by means of a fiber optic Fabry Perot interferometer sensor, Sens. Actuators A Phys. 2005, 118, 177 182... 

Based on the way the interferometer is configured, CCMI sensors can be categorized into two groups, namely the Mach-Zehnder interferometer (MZI) type and the Michelson interferometer (MI) type. The MZI sensor works in transmission mode, i.e., the transmitted interference signal is detected. The MI sensor works in reflection mode, where the light passes the interferometer twice and the reflected interference signal is detected. 

The principle of operation of a typical MZI-CCMI sensor is illustrated in Fig. 7.17a, where two mode splitters/combiners (MSC) are created on a singlemode fiber. These two MSCs are separated by a distance of L, which is referred to as the length of the interferometer. The input light, originally guided inside the fiber... 

The operating principles of the reviewed interferometers are well studied. However, by no means these devices are matured. For example, a mode-selective, wavelength-independent and environmental-resistant 3-dB core-cladding mode coupler is yet to be found to construct an ideal CCMI. As technology advances and research continues, we expect that more device structures will be explored and new methods will be investigated to fabricate these devices. Although the applications of these two types of sensors are yet to be explored, it is almost certain that they will find their way into real-world applications in the future. 

Tian, Z. Yam, S. S. Loock, H., Refractive index sensor based on an abrupt taper Michelson interferometer in a single mode fiber, Opt. Lett. 2008, 33, 1105 1107... 

Fig. 9.11 The calculated response of a 1.5 mm long silicon PWEF sensor in a Mach Zehnder interferometer configuration, as a film of final thickness d 2 nm and index n 1.5 grows on the waveguide surface. The normalized fractional surface coverage is also shown...

Fig. 9.13 Mach Zehnder interferometer (MZI) sensor interrogation circuit using (a) conventional linear waveguide geometry and (b) folded spiral waveguide geometry. The dashed line in (b) indicates the sensor window boundaries in this infra red camera image...

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