Abstract: A compact interrogator for the simultaneous interrogation of multi wavelength-modulated fiber optical sensors, includes a planar waveguide based demultiplexer receiving input signals from the sensors. An array of detectors is coupled to output waveguides of the demultiplexer corresponding to different nominal wavelengths. A tuning element matches the nominal wavelengths of the output waveguide to the input signals from the respective sensors to find the wavelengths of the individual sensors to be interrogated.

Abstract: Method and apparatus for real time measuring of an optical signal to noise ration (OSNR) of an optical channel is disclosed. The apparatus comprises a fiber Bragg grating for reflecting a signal component of the optical channel and for transmitting a noise component of the optical channel therethrough. Two photodetectors are provided disposed at two ends of the fiber Bragg grating for detecting a fraction of the reflected signal component and the transmitted noise component respectively. Electrical outputs of the photodetectors are communicated to a microprocessor for determining the OSNR. The invention provides a simple, compact, reliable, relatively fast and inexpensive technique to monitor OSNR.

Abstract: An optical based identification system that is easily deployable and can be used in broad daylight. Fluorescent semiconductor nanocrystals (quantum dots) that fluoresce at specific wavelengths are distributed in a suitable polymer. The resulting mixture can then be applied as paint or on an adhesive label for application to a portion of any equipment or member of a friendly unit. The system also has a corresponding detectional processing unit which may be mounted on ordnance or on any other equipment such as aircraft. The detection unit uses a laser, which when active, causes a laser beam to strike the paint or adhesive able applied to the friendly unit. This causes the quantum dots to fluoresce. The fluorescence of the quantum dots can be detected by the sensor portion of the detection/processing unit.