Abstract: A fiber optic perimeter detection system includes a receiver to receive output light signals from sensors positioned at different regions, each sensor including a sensing fiber. Each sensor generates an output light signal having a specified wavelength, the output light signal having a property that varies when stress is induced in the sensing fiber. The perimeter detection system includes a memory to store information related to a mapping between the wavelengths of the output light signals and the regions where the sensors are positioned.

Abstract: In general, in one aspect, the invention features assemblies that include a first polarizing beam splitter positioned in the paths of a pair of initial beams, the polarizing beam splitter being configured to combine the pair of initial beams to form an input beam. The assemblies further include an interferometer positioned to receive the input beam and configured to produce an output beam that includes information about an optical path difference between the paths of two component beams derived from the input beam. A second polarizing beam splitter is positioned in the path of the output beam and configured to split the output beam into a pair of secondary output beams that each include information about the optical path difference between the component beam paths.

Abstract: In general, in one aspect, the invention features assemblies that include a first polarizing beam splitter positioned in the paths of a pair of initial beams, the polarizing beam splitter being configured to combine the pair of initial beams to form an input beam. The assemblies further include an interferometer positioned to receive the input beam and configured to produce an output beam that includes information about an optical path difference between the paths of two component beams derived from the input beam. A second polarizing beam splitter is positioned in the path of the output beam and configured to split the output beam into a pair of secondary output beams that each include information about the optical path difference between the component beam paths.

Abstract: A light filtering assembly for filtering an input beam of light having a plurality of desired wavelength components and a plurality of unwanted wavelength components so as to provide an output beam having only the desired wavelength components. The filtering assembly comprises an input section, a filtering section, and an output section. The input section divides the input beam into a plurality of polarized beamlets that travel along a corresponding plurality of spatially separated beam paths. The polarized beamlets comprise a plurality of desired beamlets corresponding to the desired wavelength components of the input beam and a plurality of unwanted beamlets corresponding to the unwanted wavelength components of the input beam. The filtering section is disposed in the paths of the beamlets so that the desired beamlets are passed and the unwanted beamlets are blocked.

Abstract: A light filtering assembly for filtering an input beam of light having a plurality of desired wavelength components and a plurality of unwanted wavelength components so as to provide an output beam having only the desired wavelength components. The filtering assembly comprises an input section, a filtering section, and an output section. The input section divides the input beam into a plurality of polarized beamlets that travel along a corresponding plurality of spatially separated beam paths. The polarized beamlets comprise a plurality of desired beamlets corresponding to the desired wavelength components of the input beam and a plurality of unwanted beamlets corresponding to the unwanted wavelength components of the input beam. The filtering section is disposed in the paths of the beamlets so that the desired beamlets are passed and the unwanted beamlets are blocked.

Abstract: A fused coupler optical switch (FCOS) of the present invention is an electrically switchable device that functions as a latching bi-directional optical cross bar switch with a first and a fourth optical ports at a first end, and, a second and third ports at a second end of the coupler, where a magnetic sleeve surrounds the second end of the coupler. A first stop block maintains the coupler in a first mechanical position and a second stop block maintains the coupler in a second mechanical position, where the first and second stop blocks are V-grooved stop blocks. In the first position, the first port is optically connected with the third port and the fourth port is connected with the second port. In the second position, the first port is optically connected with the second port and the fourth port is connected with the third port. The inventive optical switch may include a sensor element such as a Hall element for detecting the state of the optical switch.