Abstract: An apparatus and method employing a plurality of light emitting devices which each can get light through a respective optical fiber toward a respective sample of a plurality of samples in a time-staggered manner. Light is generated in each of the samples at different times consistent with the times at which light is irradiated onto the sample. A single detector is used to detect the lights emitted from the plurality of samples at these different times. A plurality of bifurcated optical cable are coupled to the light emitting devices and single light detector, and the integrated end of each bifurcated cable acts as the light emitting port and light detecting port. Multiple targets can be detected from each of the plurality of samples in the same manner by providing an apparatus and method employing a different plurality of light emitting devices and single detector for each target to be detected.

Abstract: An apparatus and method employing a plurality of light emitting devices which each can get light through a respective optical fiber toward a respective fluid sample of a plurality of fluid samples in a time-staggered manner. Light is generated in each of the fluid samples at different times consistent with the times at which light is irradiate onto the sample. A single detector is used to detect the lights emitted from the plurality of samples at these different times. A plurality of bifurcated optical cable are coupled to the light emitting devices and single light detecting device, and the integrated end of each bifurcated cable acts as the light emitting port and light detecting port.

Abstract: An optical sensor is described comprising a first optical fiber and a first reflective member. The first optical fiber has a first predetermined length of graded-index multimode optical fiber attached to its end. The first reflective member and the first optical fiber are arranged such that a gap is formed between the unattached end of the graded-index multimode optical fiber and the first reflective member. Also described is a rugged sensor design incorporating the first optical fiber and first reflective sensor as well as a method for providing the predetermined length of graded-index multimode fiber at the end of the first optical fiber. Finally, a readout system for an optical sensor is also described which comprises two optical paths differing in length by an amount equal to an optical path distance in the optical sensor. The readout system also comprises an optical source having a wavelength differing from that of the optical sensor, a modulator and a controller.

Abstract: A device and method are described for measuring changes association with a gap between a lead-in optical fiber and a lead-out optical fiber. A hybrid fiber optic sensor is created by inserting the lead-in and lead-out optical fibers into a small tube such that a gap is provided between the fibers. Laser pulses incident on the gap create two interfacial reflections that interfere with one another, thus providing a method of measuring changes in gap length in the same was as a typical Fabry-Perot type interferometer. Moreover, a reflection from the far end of the lead-out fiber gives gap information in the same way as typical intensity-based sensor. Together the two measurements overcome the limitations that occur when each technique is used separately, and are made possible by means of the above hybrid fiber optic sensor which contains both a Fabry-Perot interferometer portion and an intensity-based sensor portion.

Abstract: A method for sensing an environmental parameter includes the step of sensing the environmental parameter with an interferometer sensor that has a light source emitting a tunable wavelength of light and a gap that changes in length in response to the environmental parameter. The interferometer has a sinusoidal output curve that oscillates in intensity in response to changes in gap length. The wavelength of light emitted by the light source is tuned to a first wavelength to provide a first output value. Similarly, the wavelength of light emitted by the light source is next tuned to a second wavelength to provide a second output value. The first and second output values correspond to points on the sinusoidal output curve that differ by at least half a cycle. The gap length is then calculated from the values of the first wavelength and the difference between the first and second wavelengths. Finally, the value of the environmental parameter is determined from the value of the gap length.