Optical drop apparatus, optical add apparatus, and optical add/drop apparatus

An optical drop apparatus comprising R routes (R is an integer of 2 or more) and coherent transponders available to simultaneously receive optical signals, the optical drop apparatus comprising:

• R wavelength separation units corresponding to the respective routes, each of which M-branches a wavelength multiplexed optical signal of one route, the coherent transponders being available to simultaneously receive optical signals with N wave lengths (N is an integer of 2 or more and M is an integer satisfying N×M=the number of multiplexed wavelengths of the wavelength multiplexed optical signal);
• and
• M wavelength separation blocks, each of which is input with optical signals branched by the different wavelength separation units and selectively outputs the input optical signals to N coherent transponders in units of M wavelength groups, each of which includes N wavelengths, each of M wavelength separation blocks reducing the maximum number R×N of wavelengths dropped from the R routes to the maximum number N of wavelengths simultaneously received by one of the coherent transponders,
• wherein N is equal to the number of the coherent transponders per wavelength separation block and is equal to the number of the wavelengths available to be simultaneously received by each coherent transponder.

An optical add/drop apparatus comprising R route (R is an integer of 2 or more) and comprising coherent transponders capable of simultaneously receiving optical signal, comprising:

• R wavelength separation units corresponding to the respective routes, each of which divides a wavelength multiplexed optical signal of one route into M wavelength groups, each of which includes N wavelengths, the coherent transponders being capable of simultaneously receiving optical signals with N wave lengths (N is an integer of 2 or more and M is an integer satisfying N×M=the number of multiplexed wavelengths of the wavelength multiplexed optical signal);
• M wavelength separation blocks, each of which is input with a plurality of the wavelength groups divided by the different wavelength separation units and outputs optical signals having any one or a plurality of wavelengths included in the input wavelength groups to N coherent transponders, each of M wavelength separation blocks reducing the maximum number R×N of wavelength dropped from the R routes to the maximum number N of wavelengths simultaneously received by one of the coherent transponders;
• M wavelength multiplexing blocks, each of which wavelength-multiplexes optical signals transmitted from different N coherent transponders;
• and
• R wavelength selection switches, each of which is installed corresponding to each route to selectively output wavelength multiplexed optical signals transmitted form different wavelength multiplexing blocks to the corresponding route in units of wavelength, each of wavelength multiplexing blocks switching and transmitting the wavelength multiplexed optical signals selectively to the wavelength selection switches corresponding to the different routes.