Optical transmitting and receiving system

An optical transmitting and receiving system comprising:

• a first MHU configured to perform wavelength division multiplexing on a first downlink signal to a fourth downlink signal and transmit the multiplexed downlink signal;
• a first ROU configured to perform demultiplexing on the multiplexed downlink signal received from the first MHU to output the first downlink signal and the second downlink signal, and transmit the multiplexed downlink signal;
• and
• a second ROU configured to perform demultiplexing on the multiplexed downlink signal received from the first ROU to output the third downlink signal and the fourth downlink signal.

An optical transmitting and receiving system comprising:

• a first MHU configured to perform wavelength division multiplexing on a first downlink signal to a fourth downlink signal and transmit the multiplexed downlink signal to an ODU;
• a first ROU configured to perform demultiplexing on the multiplexed downlink signal received from the ODU to output the first downlink signal and the second downlink signal;
• and
• a second ROU configured to perform demultiplexing on the multiplexed downlink signal received from the ODU to output the third downlink signal and the fourth downlink signal.