PURPOSE: To improve the speed of information transmission and a signal to noise ratio by utilizing the state of polarization, frequency and phase of light waves as individual encoded state selecting one of them, and transmitting to a remote as a code string, making other light waves interfere with it and reproducing obtained information.
CONSTITUTION: A luminous flux corresponding to information to be transmitted is emitted from a ray 1, and a polarization state modulator 2, a frequency modulator 3, a phase modulator 4 and a amplitude modulator 5 are operated successively by a code controller 7 to which a code generator 6 is connected. Then, the output from the modulator 5 is transmitted to a remote place through a transmission medium 8, and inputted to an interfering device 11, and the state of polarization is decided by using a polarizing state judging device 9, and interfered by a luminous flux from a station light source 10. Then, frequency, phase, amplitude are decided by using a frequency deciding device 13, a phase deciding device 14 and an amplitude modulator 15, and a code string is reproduced by a code reproducer 17. Thus, frequency component other than transmission frequency is removed by utilizing heterodyne detection, and large capacity and high quality transmission is performed.
TSUBOKAWA MAKOTO
AOMI YOSHIYUKI
Next Patent: JPS6364419