OPTICAL COMMUNICATION SYSTEM, OPTICAL COMMUNICATION UNIT, AND COMMUNICATION LINE SWITCHING METHOD

PROBLEM TO BE SOLVED: To shorten a switching time of switching of a communication line from an in-operation line to a standby line.SOLUTION: An optical communication system 1 is configured to switch a communication line between an in-operation line and a standby line. A first pre-equalization optical transmitter receiver 10 has a first optical transmitting/receiving function part 14 for transmitting an optical signal including a redundancy code for detecting a code error, and a first control part 17 for adjusting a wavelength dispersion compensation value of the optical signal. A second pre-equalization optical transmitter receiver 20 has a second optical transmitting/receiving function part 24 for receiving the optical signal, and a second control part 27 for detecting a code error rate of the optical signal. When the communication line is switched, the first control part 17 increases a rate of the redundancy code of the optical signal, the second pre-equalization transmitter receiver 20 transmits information, based upon the code error rate of the optical signal having been increased in ratio of redundancy code, to the first pre-equalization optical transmitter receiver 10, and the first control part 17 adjusts the wavelength dispersion compensation value of the optical signal based upon the information received from the second pre-equalization optical transmitter receiver 20.SELECTED DRAWING: Figure 1 【課題】通信回線を運用系回線から予備系回線に切り替えるときの切り替え時間を短縮する。【解決手段】光通信システム１は、運用系回線と予備系回線との間で通信回線の切り替えが可能であり、第１の予等化光送受信器１０は、符号誤りを検出するための冗長符号を含む光信号を送信する第１の光送受信機能部１４と、光信号の波長分散補償値を調整する第１の制御部１７とを有し、第２の予等化光送受信器２０は、光信号を受信する第２の光送受信機能部２４と、光信号の符号誤り率を検出する第２の制御部２７とを有し、通信回線が切り替わるときに、第１の制御部１７は、光信号における冗長符号の割合を増加させ、第２の予等化光送受信器２０は、冗長符号の割合が増加された光信号の符号誤り率に基づく情報を第１の予等化光送受信器１０に送信し、第１の制御部１７は、第２の予等化光送受信器２０から受信した情報に基づいて光信号の波長分散補償値を調整する。【選択図】図１