OPTICAL SIGNAL TRANSMITTING METHOD

摘要

PROBLEM TO BE SOLVED: To improve the efficiency of photodetection by performing modulation while selecting the direction of polarization of mutually orthogonal two straight lines according to the level of binary digital signals transmitted by a transmission side, making a laser beam received by a receiver side incident on a polarizer, extracting an intensity-modulated optical signal and using the other optical wave emitted from the polarizer as a detection beam for tracking. SOLUTION: The laser beam 4 emitted from a laser oscillator 1 is polarized by a straight line polarizer 5 and generates light 6 polarize-modulated to two kinds of polarizations whose straight polarizing directions are orthogonally crossed to modulate a transmission signal through the use of an electrooptical light modulator 2. After modulation, a transmission laser beam 7 is emitted from a transmitting telescope 3 to a receiver side. The receiver side receives a received laser beam 12 by a receiving telescope 8 to be made incident on a polarizing beam splitter 9. An optical signal receiver 10 detects a signal polarize-modulated by the transmitter side. Polarizing beam splitter reflection light 14 is made incident on a two-dimensional optical sensor 11 and used for tracking.