The purpose of the present invention is to suppress, with a low computational load, inter-mode interference caused by optical axis shift, tilt, reflected waves, etc., between a transmission UCA and a reception UCA. [Solution] A transmission station is provided with: multiple transmission weight multiplying units which input multiple transmission signal series, multiply the transmission signal series by a transmission weight and convert the result to MTX signals corresponding to the UCAs configuring an M-UCA, and output the same; and MTX transmission OAM mode generation processing units which input the signals corresponding to the UCAs, perform a discrete Fourier transform, and output the results to the corresponding UCAs. A receiving station is provided with: MRX receiving OAM mode separation processing units which input the signals from the UCAs configuring the M-UCA, perform a reverse Fourier transform, and output the results for each received signal series; and multiple receiving weight multiplying units which multiply each received signal series by a receiving weight, separate the received signal series which were transmitted with spatial multiplexing, suppress interference between the spatially multiplexed AOM modes and outputs the results.
OAM MULTIPLEXING COMMUNICATION SYSTEM AND INTER-MODE INTERFERENCE ELIMINATION METHOD