CWDM and DWDM are two mainstream Wavelength Division Multiplexing (WDM) optical module technologies widely used in MAN, 5G fronthaul, data center interconnection and telecom backbone networks. This article explains their working principles, standard wavelength grids, core differences, cost advantages and applicable scenarios.

1. Basic Introduction to WDM Technology

At present, WDM (Wavelength Division Multiplexing) technology is developing very rapidly, and has shown great vitality and bright prospects for development. Optical wavelength division multiplexing (WDM) is a technology that allows two or more optical wavelength signals to transmit information through different optical channels at the same time in the same optical fiber. Optical wavelength division multiplexing includes CWDM and DWDM.

2. What is CWDW optical module?

CWDM optical module (CWDM) adopts CWDM technology, which is a low-cost WDM transmission technology oriented to the access layer of MAN. In principle, CWDM uses optical multiplexers to multiplex optical signals of different wavelengths into a single optical fiber for transmission. At the receiving end of the link, the mixed signal in the optical fiber is decomposed into signals of different wavelengths by means of optical demultiplexer and connected to the corresponding receiving equipment.

Wavelength: 1270~1610nm

Front wave: 1270~1450nm

Back wave: 1470~1610nm

There are 18 wavelengths.

3. What is DWDW optical module?

The DWDM optical module uses Dense Wavelength Division Multiplexing technology, uses the bandwidth and low loss characteristics of single-mode optical fibers, and uses multiple wavelengths as carriers, allowing each carrier channel to transmit simultaneously in the optical fiber.

Wavelength: 1528.77~1563.86nm

4. Application Scenario Selection Guide

WDM (Wavelength Division Multiplexing) technology is developing rapidly. In order to meet the market requirements, ETU-Link continuously develops new products and improves product categories, both CWDM and DWDM optical transceivers are provided, which is a trustworthy optical module manufacturer.

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Understanding the Core Differences Between CWDM and DWDM

Last updated: July 13, 2026