Many network engineers and project designers often ask: What is a CWDM optical module? How does CWDM technology work? What are its core advantages and industry standards? Which scenarios are suitable for CWDM transceivers?

According to the packaging optical transceiver can be divided into packages such as GBIC, SFP, XENPAK, SNAP12, X2, XFP, SFP +, QSFP/QSFP+, CFP, CXP etc, according to the transmission rate can be divided into such as 1.25G, 10G and 25G, 40G, 100G and more. This article fully explains CWDM principles, specifications, advantages, applications and selection tips to help you deploy cost-effective wavelength division networking.

CWDM optical module is a optical fiber modules that combines CWDM technology, can be used with wavelength division multiplex connections, using the principle of wavelength division multiplexer, combining different wavelengths of light signal together and transmitted through a single fiber, at the receiving end uses a wave demultiplexer to decompose the composite optical signal, thus saving fiber resources. Therefore, CWDM optical module is called a low-cost and cost-effective network solution.

CWDM is the abbreviation of Coarse Wavelength Division Multiplexing. It is a mature optical multiplexing technology with 20nm wavelength channel spacing. A single optical fiber can transmit multiple independent optical signals with different wavelengths simultaneously, which greatly improves fiber utilization. CWDM optical modules are mainstream low-cost wavelength division transceivers widely used in access networks, metropolitan area networks and medium-distance links.

CWDM Standard Wavelength List
1270nm、1290nm、1310nm、1330nm、1350nm、1370nm、1390nm、1410nm、1430nm、1450nm
1470nm、1490nm、1510nm、1530nm、1550nm、1570nm、1590nm、1610nm

CWDM follows the ITU-T G.694.2 standard, with a total of 18 standard wavelengths ranging from 1270nm to 1610nm and fixed 20nm channel spacing. This wide spacing reduces the requirement for laser temperature control, which is one of the key reasons for its low cost.

• RoHS compliant;
• Meets the IEEE standard 802.3 (gigabit Ethernet 802.3 z,802.3 ah, FastE 802.3 u);
• Fibre channel physical interface specification FC - PI - 2;
• Compatible SONET/SDH optical standards;
• Conforms to the SFP multi-source agreement (MSA).

In addition to the above basic standards, mainstream CWDM modules also support DDM/DOM digital diagnostic monitoring, which can real-time monitor operating temperature, transmit/receive optical power and laser bias current. High-speed CWDM4 modules also comply with CWDM4 MSA specifications for 100G data center links.

• Transparent data transmission;
• Voluminous and make full use of the fiber's huge bandwidth resources;
• CWDM technology saves fiber resources greatly, effectively reduce construction cost;
• Network flexibility, stability and reliability;
• Compatible all-optical network switching and achieve a long distance relay-less transmission;
• The simplification of laser module that reduce the volume of the equipment, greatly saves floor space;
• Light layer recovery be independent, which can effectively protect data transmission;
• Low insertion loss, low polarization dependent loss.

Advantages and feature analysis:
Low equipment cost: No need for high-precision cooled lasers and complex wavelength locking components, far lower than DWDM solutions, suitable for large-scale deployment.
Passive networking support: Matched with passive CWDM MUX/DEMUX multiplexer, no extra power supply is required for node equipment, simplifying on-site power layout.
Flexible expansion: Channels can be added step by step according to business growth without re-laying optical fibers, protecting early investment.
Moderate transmission distance: The maximum relay-free transmission distance can reach 20~80km, meeting most metropolitan area and access link requirements.

Ⅳ.What Are the Main Application Scenarios of CWDM Optical Modules?

CWDM optical modules are widely used in CATV (cable TV), FTTH (fiber to the home), 1G and 2G fiber channel, MB and gigabit Ethernet, synchronous optical network SONET OC - 3 (155 MBPS), OC - 12 (622 MBPS) and OC - 48 (2.488 Gbps), security and protection system, etc.

As a cost-effective wavelength division solution, CWDM optical modules solve the problem of insufficient fiber resources in network construction. With low cost, flexible networking and stable performance, they are widely used in FTTH, metropolitan networks, data centers, security monitoring and other fields. Select corresponding packaging and rate specifications according to transmission distance and business volume to maximize project benefits.

ETU-Link can supply various types of CWDM optical modules, with high cost performance and strong stability, which can be 100% compatible with many big brands, such as Cisco, Huawei, H3C, HP, etc. The stability is guaranteed by multiple high quality testing before shipment. ETU-Link can also provide users with system solutions to help users build low-cost, cost-effective and easy to manage network systems.

For more details, please visit our website www.etulinktechnology.com.