Wavelength Division Multiplexing (WDM) is a technology used in fiber-optic communications to increase bandwidth by allowing different data streams to be sent simultaneously over a single optical fiber. This is achieved by multiplexing multiple optical carrier signals, each assigned a unique wavelength (or color) of light. Each wavelength acts as a separate virtual fiber or channel, carrying an independent signal. A multiplexer combines these signals at the transmitter, and a demultiplexer separates them at the receiver.

1. Huawei Technologies Co.

Ltd. (2021). WDM Basics - Feature Description. In iMaster NCE-T & U2000 WDM OTN Feature Parameter Reference. Section: WDM Basics. The document states

"Wavelength division multiplexing (WDM) is a technology that transmits multiple optical signals of different wavelengths in the same fiber."

2. Kaminow

I. P.

& Li

T. (Eds.). (2002). Optical Fiber Telecommunications IV-A: Components. Academic Press. In Chapter 1

"Introduction

" Section 1.1

it is explained that WDM involves "the transmission of many different-wavelength channels over a single fiber."

3. Agrawal

G. P. (2010). Fiber-Optic Communication Systems (4th ed.). Wiley. In Chapter 7

"Optical Amplifiers

" Section 7.1

the text introduces WDM by stating

"The technique of transmitting several channels simultaneously

each at a different carrier wavelength

is known as wavelength-division multiplexing (WDM)." (DOI: 10.1002/9780470916685)