Abstract: An improved system for acquiring and tracking an optical beam. In the illustrative application, the inventive system is used to facilitate optical communication between two satellites and provides an improved technique for acquiring and tracking two optical beams. The illustrative embodiment includes an optical transmitter (26) mounted on the first satellite for transmitting a first optical beam. The beam is scanned over a predetermined area in a predetermined pattern at a predetermined rate. When the beam is detected at the second satellite, the receiver at the second satellite generates a signal indicative of the time at which the beam is detected. This signal is used to modulate a second beam transmitted by the second satellite. The second beam is scanned over a predetermined area in a predetermined pattern at a predetermined rate.

Abstract: A satellite communications system. The inventive system (10) includes an arrangement (11) disposed on a first satellite for transmitting a plurality of unidirectional beams of electromagnetic radiation (32, 34, 36 and 38). Each beam is transmitted by an optical fiber (22, 24, 26 and 28) and has a unique modulation and a known coverage area. At least one of the beams (34) is received by a remote satellite receiver (30) which retransmits a signal with the modulation of the received beam. The retransmitted signal is received at the first satellite and the modulation thereon is extracted to identify which beam was received by the remote satellite. This information is used to change the coverage of the transmitted beams until the remote satellite detects all of the transmitted beams. At this point, data communication in the normal course may be effected.

Abstract: A system for sensing temperature at a plurality of locations, wherein a laser diode device (12) is used as a temperature sensing element at each of the plurality of locations, includes a corresponding plurality of modulators (30) for uniquely modulating each laser diode device (12) at a unique frequency or at a unique temporal code. The uniquely modulated laser diode devices (12) produce uniquely modulated single-mode wavelength outputs of radiation which are collected by a spectrometer (18). However, the single-mode wavelength output of each laser diode device (12) is sensitive to temperature and therefore varies over temperature. Thus, the spectrometer (18) groups the single-mode wavelength outputs of the laser diode devices (12) according to wavelength, or temperature, and converts the grouped wavelengths into multi-modulated electrical signals (20).