opticalnetwork

An optical network (referred to here as opticalnetwork) is a communications infrastructure that primarily uses optical fiber and light signals to transport information. It covers core backbone, regional and metro, and access networks, and it supports high bandwidth and long-haul transmission. Modern optical networks frequently use wavelength-division multiplexing to carry multiple channels on a single fiber.

Key components include optical fibers (usually single-mode), light sources such as DFB and external-cavity lasers, photodetectors, and inline amplifiers (EDFA, Raman). Passive components like multiplexers/demultiplexers, couplers, optical add-drop multiplexers, and ROADM enable wavelength routing. Transponders and optical switches convert signals to optical form and back, while dispersion compensation maintains signal quality.

Technologies include dense and sparse WDM (DWDM, CWDM), coherent detection with digital signal processing, and forward error correction. Networks use point-to-point, meshed, or ring topologies with protection and restoration. Access networks often employ passive optical networks (PON) to deliver services to end users.

Standards from ITU-T, IEEE, and IEC define fiber types, wavelength grids, and framing. Common references include ITU-T G.652/G.657 fibers, G.694.1 channel spacing, and G.709 OTN framing. Coexistence with electronic networks is achieved through OTN, SONET/SDH, and Ethernet over optical transport networks.

Applications include Internet backbone, data center interconnect, metro networks, and submarine communications. Trends include higher data rates (400 Gbit/s and beyond), extended reach via coherent transmission, SDN-enabled control, and automation for dynamic provisioning of optical paths. PON remains a key access technology in many regions.