US 12,250,023 B2
Optical space communications transmission and reception terminal and optical space communications system
Keisuke Matsuda, Tokyo (JP); and Tsuyoshi Yoshida, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
Filed on Mar. 30, 2023, as Appl. No. 18/192,716.
Application 18/192,716 is a continuation of application No. PCT/JP2020/045909, filed on Dec. 9, 2020.
Prior Publication US 2023/0254040 A1, Aug. 10, 2023
Int. Cl. H04B 10/112 (2013.01); H04B 10/118 (2013.01)
CPC H04B 10/1123 (2013.01) [H04B 10/118 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An optical space communications transmission and reception terminal that performs bidirectional communication with a pair of optical space communications transmission and reception terminals having a same configuration, the optical space communications transmission and reception terminal comprising:
an optical transceiver to convert transmission data into a transmission optical signal modulated at a symbol rate synchronized with a transmission clock signal and output the transmission optical signal, and generate received data by demodulating and decoding a signal obtained by sampling a received optical signal at a cycle synchronized with a reception clock signal;
an intensity modulator to generate a transmission optical signal obtained by superimposing a transmission clock signal on the transmission optical signal output from the optical transceiver and performing intensity modulation, and output the generated transmission optical signal;
a transmission clock source to supply a common transmission clock signal to the optical transceiver and the intensity modulator;
a fiber coupler to output an intensity-modulated transmission optical signal as collimated light and couple the input optical signal to an optical fiber;
an optical fiber amplifier to amplify an optical signal coupled to the optical fiber by the fiber coupler and output the amplified optical signal to the optical transceiver as a received optical signal;
a tracking mirror to output an optical signal propagated in space to a side of the fiber coupler, output the transmission optical signal collimated by the fiber coupler to the space, and output, when a propagation angle error is input, an optical signal in which a propagation angle is corrected on a basis of the input propagation angle error;
a beam splitter to divide a part of an optical signal propagating between the tracking mirror and the fiber coupler; and
an angle sensor to output a propagation angle error detected from the optical signal divided by the beam splitter to the tracking mirror, and output a clock signal extracted from the optical signal divided by the beam splitter to the optical transceiver as a reception clock signal.