Optical add/drop multiplexer

An optical add/drop multiplexer, comprising:

• a) one or more optical drop multiplexers connected in free space or fused by fiber pigtails;
• b) a wavelength blocker;
• c) one or more optical add multiplexers connected in the free space or fused by fiber pigtails;
• d) a digital signal processor;
• e) an analog-to-digital signal converter;
• f) a digital-to-analog signal converter;
• and
• g) a plurality of electronic control and feedback loops;
• wherein
• the optical drop multiplexer comprises three ports:
• an input port used for receiving a multi-wavelength signal, a drop port used for outputting a drop signal, and an output port used for transmitting the multi-wavelength signal to a next optical drop multiplexer or to an input port of the wavelength blocker;
• the input port of the wavelength blocker is connected to the output port of the optical drop multiplexer through the fusion of the fiber pigtails, and is used to receive the multi-wavelength signal, block a selected wavelength, and transmit other wavelengths to an output port;
• the optical add multiplexer comprises three ports:
• an input port connected to the output port of the wavelength blocker, and used to receive the multi-wavelength signals except the drop signal, an add port used for inputting an add signal, and an output port used for transmitting the multi-wavelength signal to the next optical add multiplexer or to a multi-wavelength signal processing system;
• the digital signal processor is used for receiving, outputting, and processing digital and analog electronic signals;
• the analog-to-digital signal converter is used for receiving an optical power signal output from the drop multiplexer and the add multiplexer, and converting an analog signal into a digital signal, and outputting the digital signal to the digital signal processor for signal processing;
• the digital-to-analog converter is used for receiving a signal sent from the digital signal processor, converting the digital signal into an analog signal, and outputting the analog signal to a radio frequency signal source for tuning the wavelength of the drop or add signal;
• and
• the plurality of electronic control and feedback loops are used for tuning and scanning an optical wavelength.