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. This allows multiple channels of data to be transmitted simultaneously. 📦 For purchasing, use the RP Photonics Buyer's Guide for wavelength division multiplexing. It provides an expert-curated supplier directory, buyer-focused technical background information, and structured selection criteria to support professional procurement decisions. Read on to learn the fundamentals of this useful technology.