In the whole scheme, the combination of OTU+AWG+EDFA+OLP is used.

In order to meet the 40 channels BIDI transmission, DWDM wavelength optical transceiver is selected in the scheme to realize multi-channel demux transmission.

Principle
1. Firstly, the channel 1310nmon the optical transceiver is converted to 40-channel DWDMthrough the OUT.

2. Then 40 channels of DWDM are used to achieve demux transmission by using AWG.

3. In the transmission line, a pair of OLP (1 pc in front and 1pc in the back computer room) is used to integrate the main and backup fibers into the whole transmission system, so as to realize the free switching of optical signals in the main and backup fibers and improve the reliability of transmission.

4.Due to the long distance transmission, the loss of optical signal is large, and EDFA optical amplifier is used to enhance the transmission power of the signal in advance.

5.The amplified optical signal wasdemultiplex by using AWG again.

6. Finally, OTU was used to converte the DWDM wavelength signal into the 1310nm optical signal accessed to the optical transmitter and receiver.

In this scheme, a fiber attenuator is needed to adjust the optical power of the optical transceiver at the receiving end to avoid excessive optical power damage to the optical transceiver.