| 摘要 |
A receiver including an analyzer and a detector coupled to the output of the analyzer. The analyzer selects a polarized component of a return beam for input to the detector. The analyzer may be linear, circular or elliptical. Coupled with a laser adapted to output a polarized beam, the receiver provides an active optical target detector. An arrangement may be included for compensating for rotation and ellipticity in the returned beam. In one embodiment, the arrangement for compensating for rotation of the orientation of linear polarization in the returned beam includes a Faraday rotator positioned between the transmitter and the analyzer. An arrangement is disclosed for varying the rotation in the returned beam using a Faraday rotator until a maximum transmittance is achieved. In an alternative embodiment, the arrangement for compensating for ellipticity in the returned beam includes an electro-optical modulator positioned between the transmitter and the analyzer. In another alternative embodiment, two electro-optical modulators are included to compensate for any change in the polarization state in the returned beam.
|
