{"id":6944,"date":"2025-08-19T00:00:00","date_gmt":"2025-08-19T00:00:00","guid":{"rendered":"https:\/\/lp.szlogic.cn\/knowledge-center\/100g-cwdm4-lr4-single-mode-fiber-key-differences-use-cases\/"},"modified":"2026-06-22T08:20:19","modified_gmt":"2026-06-22T08:20:19","slug":"100g-cwdm4-lr4-single-mode-fiber-key-differences-use-cases","status":"publish","type":"post","link":"https:\/\/resources.l-p.com\/pt\/knowledge-center\/100g-cwdm4-lr4-single-mode-fiber-key-differences-use-cases","title":{"rendered":"Comparing QSFP28 100G CWDM4 and LR4 for Single-Mode Fiber Deployments"},"content":{"rendered":"<figure class=\"wp-block-image aligncenter size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/8244e8dc75e24b2e8a1ec07d6aada7cb.webp\" alt=\"100G CWDM4 VS LR4\" class=\"wp-image-6942\" srcset=\"https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/8244e8dc75e24b2e8a1ec07d6aada7cb.webp 1200w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/8244e8dc75e24b2e8a1ec07d6aada7cb-300x178.webp 300w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/8244e8dc75e24b2e8a1ec07d6aada7cb-1024x608.webp 1024w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/8244e8dc75e24b2e8a1ec07d6aada7cb-768x456.webp 768w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/8244e8dc75e24b2e8a1ec07d6aada7cb-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>How to choose between QSFP28 100G CWDM4 and LR4 modules for your data center?<\/strong> These two dominant <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-27045-100g-qsfp28-sfp-dd.htm\"><strong>100G optical transceiver<\/strong><\/a> standards look similar but have critical differences impacting cost, reach, and infrastructure. This guide cuts through the complexity, empowering you to make the <strong>perfect<\/strong>, <strong>cost-effective choice<\/strong> for your high-speed links.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Key Takeaways<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p>Pick <strong>100G CWDM4 modules<\/strong> for short or medium distances <strong>up to 2km<\/strong>. These modules help you save money and use less power. They still give good performance.<\/p><\/li><li><p>Use <strong>100G LR4 modules<\/strong> for long distances <strong>up to 10km<\/strong>. These modules give strong and reliable signals. You need to spend more for them.<\/p><\/li><li><p>Check if your network equipment works with the modules before you buy. Make sure the modules fit your switches and routers.<\/p><\/li><li><p>Think about how far your network needs to go and your budget. Pick the module that matches your needs now and in the future.<\/p><\/li><li><p>Know that <strong>CWDM4 uses direct modulation lasers<\/strong> and needs error correction. <strong>LR4 uses external modulation lasers<\/strong> for longer reach and may not always need error correction.<\/p><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Understanding the Core Technologies<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Both <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/472577.htm\"><strong>QSFP28 CWDM4<\/strong><\/a> and <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/472118.htm\"><strong>QSFP28 LR4<\/strong><\/a> are hot-pluggable, 100GBase transceivers using four 25Gbps lanes. Their core divergence lies in <strong>wavelength multiplexing<\/strong> and <strong>link budget<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\" >\n<li><p style=\"margin: 0px 0px 4px;\"><strong>QSFP28 100G CWDM4 Transceiver (100GBase-CWDM4):<\/strong><\/p><ul><li><p style=\"margin: 0px;\"><strong>Wavelengths:<\/strong> Uses four wavelengths within the <strong>Coarse Wavelength Division Multiplexing <\/strong><a target=\"_blank\" rel=\"\" href=\"https:\/\/resources.l-p.com\/pt\/glossary\/what-is-cwdm-understanding-coarse-wavelength-division-multiplexing\/\"><strong>(CWDM)<\/strong><\/a> grid: approximately <strong>1271nm, 1291nm, 1311nm, and 1331nm<\/strong>.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Reach:<\/strong> Optimized for <strong>up to 2 km<\/strong> over standard <a target=\"_blank\" rel=\"\" href=\"https:\/\/resources.l-p.com\/pt\/knowledge-center\/what-is-single-mode-fiber-and-how-does-it-work\/\"><strong>single-mode fiber<\/strong><\/a><strong> (SMF)<\/strong>.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Key Advantage:<\/strong> <strong>Cost-effectiveness<\/strong>. Leverages wider channel spacing, allowing simpler (cheaper) lasers and optics. Crucial for <strong>high-density data center<\/strong> deployments where <strong>power consumption<\/strong> and <strong>optic module price<\/strong> are paramount.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Fiber Usage:<\/strong> Uses <strong>dual single-mode fiber (SMF)<\/strong> strands (one for Tx, one for Rx) \u2013 a <strong>pair of fibers<\/strong>.<\/p><\/li><\/ul><\/li><li><p style=\"margin: 0px 0px 4px;\"><strong>QSFP28 100G LR4 Transceiver (100GBase-LR4):<\/strong><\/p><ul><li><p style=\"margin: 0px;\"><strong>Wavelengths:<\/strong> Uses four tightly packed wavelengths around the 1310nm window (<strong>1295.56nm, 1300.05nm, 1304.58nm, 1309.14nm<\/strong>) based on <a target=\"_blank\" rel=\"\" href=\"https:\/\/resources.l-p.com\/pt\/glossary\/what-is-lwdm-and-why-important-for-lans\/\"><strong>LAN-WDM<\/strong><\/a> technology.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Reach:<\/strong> Designed for longer distances, supporting <strong>up to 10 km<\/strong> over standard <strong>single-mode fiber (SMF)<\/strong>.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Key Advantage: Reach<\/strong>. Essential for connecting <strong>campus networks<\/strong>, <strong>metro Ethernet<\/strong>, or linking <strong>disaggregated data center<\/strong> buildings.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Fiber Usage:<\/strong> Also uses <strong>dual single-mode fiber (SMF)<\/strong> strands (one for Tx, one for Rx).<\/p><\/li><\/ul><\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Head-to-Head Comparison: CWDM4 vs LR4<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Here&#8217;s a clear breakdown of the critical differences:<\/p>\n\n\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<colgroup><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><\/colgroup><tbody><tr><th colspan=\"1\" rowspan=\"1\"><p><strong>Feature<\/strong><\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p><strong>QSFP28 100G CWDM4<\/strong><\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p><strong>QSFP28 100G LR4<\/strong><\/p><\/th><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Standard<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>100GBase-CWDM4 (IEEE) \/ MSA<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>100GBase-LR4 (IEEE 802.3bm Clause 88)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Wavelength Grid<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>CWDM (~1271, 1291, 1311, 1331 nm)<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>LAN-WDM (~1295, 1300, 1304, 1309 nm)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Max Reach<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>2 km<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>10 km<\/strong><\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Fiber Type<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Single-Mode Fiber (SMF)<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Single-Mode Fiber (SMF)<\/strong><\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Fiber Count<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>2 Fibers<\/strong> (1 Tx pair, 1 Rx pair) &#x2705;<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>2 Fibers<\/strong> (1 Tx pair, 1 Rx pair)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Typical Cost<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Lower<\/strong> (Simpler lasers &amp; optics) &#x1f4b0;<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Higher<\/strong> (Tighter tolerances &amp; reach)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Power Consumption<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Typically <strong>Lower<\/strong> (&lt; 3.5W) &#x1f50b;<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Typically <strong>Slightly Higher<\/strong> (\u2264 3.5W)<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Primary Use Case<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Short-Reach Data Center Interconnects (DCI)<\/strong>, Top-of-Rack (ToR) to Leaf<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Longer-Reach DCI<\/strong>, Metro, Campus Links, Leaf to Spine\/Core<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>MSA Compliance<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>CWDM4 MSA<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>IEEE 802.3bm<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Interoperability<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Not directly interoperable<\/strong> with LR4 &#x274c;<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Not directly interoperable<\/strong> with CWDM4 &#x274c;<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Key Driver<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Cost Optimization<\/strong>, Power Efficiency<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Reach Requirement<\/strong><\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 Why the Reach Difference Matters (And When Cost Wins)<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>2km reach of CWDM4 transceiver<\/strong> is often perfect within modern <strong>hyperscale data centers<\/strong>. If your links connect racks within a row or adjacent rows in the same hall, CWDM4 delivers <strong>significant savings<\/strong> on <strong>optic module cost<\/strong> without sacrificing performance. This makes it the go-to choice for <strong>high-volume data center<\/strong> deployments prioritizing <strong>total cost of ownership (TCO)<\/strong>. <strong>LINK-PP&#8217;s <\/strong><a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/472577.htm\"><strong>LQ-CW100-FR4C<\/strong><\/a> is a market leader here, offering reliability at an optimal price point.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>10km reach of LR4 module<\/strong> is indispensable when connecting across buildings, to a <strong>central office<\/strong>, or within a <strong>metro network<\/strong>. While the <strong>optic module price<\/strong> is higher due to more precise laser requirements, it eliminates the need for potentially expensive reach extenders or additional network hops for these longer distances. For robust, future-proofed <strong>long distance fiber optic transmission<\/strong>, <strong>LINK-PP&#8217;s <\/strong><a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/472118.htm\"><strong>LQ-LW100-LR4C<\/strong><\/a> provides the necessary performance.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>&#x2705; Key Takeaways &amp; Which One to Choose<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px;\"><strong>Need \u2264 2km within a data center? Choose CWDM4.<\/strong> It&#8217;s the <strong>cost-effective<\/strong>, <strong>power-efficient<\/strong> workhorse for <strong>cloud infrastructure<\/strong>, <strong>webscale networking<\/strong>, and <strong>enterprise data center<\/strong> spine-leaf architectures. Maximize your budget without compromise.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Need up to 10km (campus, metro, inter-building)? Choose LR4.<\/strong> Its longer reach is non-negotiable for these scenarios, justifying the higher <strong>optic module price<\/strong>. Essential for <strong>telecom applications<\/strong> and <strong>extended data center interconnects<\/strong>.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Interoperability:<\/strong> CWDM4 and LR4 modules <strong>are NOT plug-and-play compatible<\/strong>. Ensure both ends of a link use the <em>same<\/em> technology (CWDM4-CWDM4 or LR4-LR4).<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Fiber Infrastructure:<\/strong> Both require standard <a target=\"_blank\" rel=\"\" href=\"https:\/\/resources.l-p.com\/pt\/knowledge-center\/what-is-single-mode-fiber-and-how-does-it-work\/\"><strong>single-mode fiber patch cables<\/strong><\/a>. The choice doesn&#8217;t impact your underlying fiber plant type, only the reach it enables.<\/p><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 LINK-PP: Your Partner for High-Performance 100G Optics<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Whether you need the <strong>cost-optimized efficiency<\/strong> of <strong>CWDM4<\/strong> for massive <strong>data center scaling<\/strong> or the <strong>extended reach<\/strong> of <strong>LR4<\/strong> for <strong>metro connectivity<\/strong>, <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.link-pp.com\/\"><strong>LINK-PP<\/strong><\/a> delivers reliable, high-quality QSFP28 solutions. Our <strong>100G CWDM4<\/strong> and <strong>100G LR4<\/strong> modules are rigorously tested for seamless <strong>100g qsfp28<\/strong> integration and performance.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/cd078f459da94d85a63b16ca949eeab4.webp\" alt=\"100G optical transceivers\" class=\"wp-image-6943\" srcset=\"https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/cd078f459da94d85a63b16ca949eeab4.webp 1200w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/cd078f459da94d85a63b16ca949eeab4-300x178.webp 300w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/cd078f459da94d85a63b16ca949eeab4-1024x608.webp 1024w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/cd078f459da94d85a63b16ca949eeab4-768x456.webp 768w, https:\/\/resources.l-p.com\/wp-content\/uploads\/2026\/05\/cd078f459da94d85a63b16ca949eeab4-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Ready to Optimize Your 100G Network?<\/strong> &#x2709;&#xfe0f;<br\/><strong>Consult with LINK-PP experts today!<\/strong> We&#8217;ll help you select the perfect <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-27045-100g-qsfp28-sfp-dd.htm\"><strong>100g transceiver<\/strong><\/a> \u2013 whether it&#8217;s <strong>CWDM4<\/strong>, <strong>LR4<\/strong>, or other cutting-edge <strong>fiber optic modules<\/strong> \u2013 ensuring maximum performance, reliability, and value for your specific <strong>data center connectivity<\/strong> needs. <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/sample.htm\"><strong>Get a quote or request samples now \u279e<\/strong><\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u27a4 FAQ<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" >What is the main difference between 100G CWDM4 and 100G LR4?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">You will find that CWDM4 works best for short to medium distances, up to 2km. LR4 supports longer distances, up to 10km. LR4 uses stronger lasers and costs more.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Do I need special equipment for CWDM4 or LR4 modules?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Most modern switches and routers support CWDM4. LR4 sometimes needs special gear for long distances. Always check your device\u2019s compatibility before you buy.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Why does CWDM4 require FEC?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">CWDM4 needs <a target=\"_blank\" rel=\"\" href=\"https:\/\/resources.l-p.com\/pt\/glossary\/fec-forward-error-correction-in-optical-communication\/\"><strong>Forward Error Correction (FEC)<\/strong><\/a> to fix errors during data transmission. FEC helps keep your data safe and reliable, especially over longer links.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Can I use CWDM4 and LR4 modules together in one network?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">You can use both types in the same network if your equipment supports them. Make sure each link uses the right module for its distance and requirements.<\/p>","protected":false},"excerpt":{"rendered":"<p>Compare 100g cwdm4 lr4 modules for single-mode fiber: CWDM4 suits short to medium links, LR4 excels at long-distance, high-reliability connections.<\/p>","protected":false},"author":1,"featured_media":6942,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[13],"class_list":["post-6944","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-knowledge-center","tag-100g-modules"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/posts\/6944","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/comments?post=6944"}],"version-history":[{"count":4,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/posts\/6944\/revisions"}],"predecessor-version":[{"id":11243,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/posts\/6944\/revisions\/11243"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/media\/6942"}],"wp:attachment":[{"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/media?parent=6944"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/categories?post=6944"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/resources.l-p.com\/pt\/wp-json\/wp\/v2\/tags?post=6944"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}