Jurgen Kordts

Loss-compensated photoelastic fiber optic pressure sensor

A fiber optic pressure sensor based on the photoelastic effect has been set up in a four-port polariscope. The down lead insensitivity is achieved by application of the balanced bridge referencing technique. The sensor has an excellent insensitivity to source intensity fluctuations as well as mode dependent and mode independent changes in the damping of the down leads. The sensor exhibits a linearity of +/-0.1% and a temperature stability of +/-1% within a range of 0-60 degrees C with respeat to a span of 6 bar.

Optical Detection Of Respiration Motion And Heart Beats For Magnetic Resonance Imaging (MRI) Applications

A fiber optical strain gauge sensor for detection of respiration motion and heart beat rhythm has been developed in order to suppress motion artifacts in magnetic resonance images (MRI) by gating and triggering procedures. A photoelastic sensing principle has been used in this sensor. It has been adapted to optical fibers to achieve a remote evaluation of the optical signals. The sensor properties are discussed and first results on image quality improvements by the application of this optical sensor are presented for the case of 2 Tesla magnetic resonance imaging of the beating human heart.

Optical Detection Of Pulse Beats For Magnetic Resonance Imaging Applications

Two different types of fiber optic sensors for the detection of human heart beats in the harsh electro magnetic environment of a Magnetic Resonance (MR) scanner have been developed. The first type is a photo elastic strain gauge belt sensor, which originally has been developed for the detection of respiratory motion. This sensor has been applied around the thigh in order to detect the pulse of the thigh artery. The second type is a fiberoptic version of a photo plethysmograph detecting the optical transmission of human tissue. A transmissive and a reflective type of this sensor have been tested by application to ear lobes, finger and toe tips respectively.

Improvements Of The Data Link Dependencies Of Fiber Optic Sensor

The precision of intensity modulated fiber optic sensor systems mainly is restricted by the damping characteristics of the analog fiber optical data link. Special encoding and referencing schemes are used to overcome this data link dependence. In this paper encoding and referencing principles for optical sensors are outlined and compared. Especially the two wavelengths referencing and the optical delay line processing techniques are discussed in more detail and results are presented.

Improvements of the data link dependencies of fiber optic sensor systems

Abstract The precision of intensity modulated fiber optic sensor systems mainly is restricted by the attenuation characteristics of the analog fiber optical data link. Special encoding and referencing schemes are used to overcome this data link dependence. In this paper encoding and referencing principles for optical sensors are outlined and compared. Especially the two wavelengths referencing and the optical delay line processing techniques are discussed in more detail and results are presented.