Principle: Employs narrow spacing (0., 1530–1565 nm), supporting 40–96 channels with 10–400 Gbps each. Applications: Long-haul (100–3000 km) and backbone networks. In fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i. Available in premium grade 1310/1550nm variations, select from light, medium and heavy duty casings. Also available are WDM modules for wallmount and rackmount, as well as termination. based on environmentally stable thin film filter technology. However, conventional fibers are not suitable at these wavelengths due to higher dispersion.