Patent ID: 11881900
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 5:
6. A spatial light frequency transmission system comprising:
a first transceiver including a photorefractive crystal, the first transceiver being configured to emit reference signal light of a reference optical frequency to space via the photorefractive crystal; and
a second transceiver including a guide light source configured to emit guide light having a first frequency different from a second frequency of the reference signal light and a frequency control unit configured to transmit the guide light from the guide light source to the first transceiver via space,
wherein the first transceiver forms, when the guide light transmitted from the frequency control unit is incident on the photorefractive crystal, a first double phase conjugate mirror in the photorefractive crystal by scattering of the guide light and the reference signal light that is incident from a reverse direction to a direction of the guide light,
the second transceiver couples, when the reference signal light that is phase-conjugate light of the guide light by the first double phase conjugate mirror is received, the reference signal light received to an optical fiber using the frequency control unit and transmits, via space, return signal light obtained by shifting a third frequency of the reference signal light after reflection to be different from the second frequency of the reference signal light and the first frequency of the guide light, and
the first transceiver forms, when the return signal light transmitted from the second transceiver is incident on the photorefractive crystal, a second double phase conjugate mirror in the photorefractive crystal by scattering of the return signal light that is incident and the reference signal light and emits the reference signal light to the second transceiver as phase-conjugate light of the return signal light by the second double phase conjugate mirror.