Abstract: An optical sensor assembly including a diffractive optical element (DOE) responsive to an optical input beam and a refractive lens responsive to a shaped optical beam from the DOE. The lens focuses the shaped optical beam to provide a center beam having a short focal length and an outer beam having a long focal length. A sensor is positioned in front of the long focal length and is responsive to the shaped input beam from the lens. A fiber is positioned within a center opening of the sensor so that an input facet of the fiber faces the DOE and is located at the short focal length. The sensor is positioned relative to the DOE and the position of the input beam is controlled so that the center beam impinges the input facet and the outer beam impinges the sensor.

Abstract: An optical sensor assembly including a diffractive optical element (DOE) responsive to an optical input beam and a refractive lens responsive to a shaped optical beam from the DOE. The lens focuses the shaped optical beam to provide a center beam having a short focal length and an outer beam having a long focal length. A sensor is positioned in front of the long focal length and is responsive to the shaped input beam from the lens. A fiber is positioned within a center opening of the sensor so that an input facet of the fiber faces the DOE and is located at the first focal length. The sensor is positioned relative to the DOE and the position of the input beam is controlled so that the center beam impinges the input facet and the outer beam impinges the sensor.

Abstract: An optical communications terminal including a polarizing element responsive to a first linearly polarized optical beam and rotating the first linearly polarized optical beam in a first linear direction, a beam separator responsive to and passing the first linearly polarized optical beam, and a circular polarizing element responsive to the first linearly polarized optical beam from the beam separator and circularly polarizing the first linearly polarized optical beam for transmission, where the circular polarizing element is switchable between two orthogonal switching states. The terminal receives a circularly polarized optical beam from another terminal and linearly polarizes the circularly polarized optical beam from the other terminal in a second linear direction that is orthogonal to the first linear direction and the beam separator directs the circularly polarized optical beam from the other terminal in a direction away from the polarizing element.

Abstract: An optical communications system including two communications terminals in communication with each other using optical signals having the same wavelength. Both terminals include a half-wave plate polarizer for rotating linearly polarized optical signals and a quarter-wave plate polarizer for circularly polarizing the optical signals. The quarter-wave plate polarizers are oriented 90° relative to each other so that circularly polarized optical signals sent from one terminal to the other terminal are linearly polarized 90° relative to a transmission polarization orientation to be separable from the transmitted optical signals by a beam splitter.

Abstract: An optical communications system including two communications terminals in communication with each other using optical signals having the same wavelength. Both terminals include a half-wave plate polarizer for rotating linearly polarized optical signals and a quarter-wave plate polarizer for circularly polarizing the optical signals. The quarter-wave plate polarizers are oriented 90° relative to each other so that circularly polarized optical signals sent from one terminal to the other terminal are linearly polarized 90° relative to a transmission polarization orientation to be separable from the transmitted optical signals by a beam splitter.