Communication device, base station, and communication system

A base station, comprising:

• a baseband unit, a remote radio unit, and a communication device;
• wherein the communication device comprises a power divider, a coupler group, and a multiplexer that are sequentially connected, wherein
• the power divider is connected to the coupler group via at least two first paths;
• the power divider is configured to divide a light beam into at least two split light beams, wherein the at least two split light beams enter the at least two first paths in one-to-one correspondence, and a phase difference and a time difference exist in transmission of any two split light beams in corresponding first paths;
• the coupler group is configured to:
• perform coupling interference on the at least two split light beams, and output at least two coupled split light beams;
• the multiplexer is connected to the coupler group via at least two second paths, the at least two coupled split light beams enter the at least two second paths in one-to-one correspondence, and a time difference exists in transmission of any two coupled split light beams in corresponding second paths;
• and
• the multiplexer is configured to perform orthogonal beam combining on the at least two coupled split light beams;
• wherein the baseband unit has a signal connection to the remote radio unit via the communication device.