{"id":8974,"date":"2026-06-01T08:54:46","date_gmt":"2026-06-01T07:54:46","guid":{"rendered":"https:\/\/yfconnectivity.com\/?p=8974"},"modified":"2026-06-01T09:09:57","modified_gmt":"2026-06-01T08:09:57","slug":"what-is-relative-refractive-index-difference","status":"publish","type":"post","link":"https:\/\/yfconnectivity.com\/fr\/what-is-relative-refractive-index-difference\/","title":{"rendered":"What Is Relative Refractive Index Difference (\u0394) in Optical Fiber?"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"8974\" class=\"elementor elementor-8974\" data-elementor-post-type=\"post\">\n\t\t\t\t<div data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" class=\"elementor-element elementor-element-9241746 e-flex e-con-boxed e-con e-parent\" data-id=\"9241746\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-23b7239 elementor-widget elementor-widget-text-editor\" data-id=\"23b7239\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p data-start=\"173\" data-end=\"428\">If you&#8217;re just stepping into the world of fiber optics, all the technical terms and abbreviations can feel overwhelming. That\u2019s why I created this <a href=\"https:\/\/yfconnectivity.com\/blog\/\">fiber glossary series<\/a> \u2014 to help you understand what these terms really mean, in the simplest way possible.<\/p><p data-start=\"430\" data-end=\"726\">I\u2019ll explain everything from an industry insider\u2019s point of view, using real photos whenever I can (not just fancy renders). I also avoid overly complex explanations, keeping the language clear and direct, so you can be confident you\u2019ll understand the real meaning of these terms after reading.<\/p><p data-start=\"728\" data-end=\"784\">Today, we\u2019re going to talk about: <strong>Relative Refractive Index Difference<\/strong><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2e80493 elementor-toc--content-ellipsis elementor-widget__width-initial elementor-hidden-desktop elementor-hidden-tablet elementor-toc--minimized-on-tablet elementor-widget elementor-widget-table-of-contents\" data-id=\"2e80493\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;no_headings_message&quot;:&quot;No headings were found on this page.&quot;,&quot;container&quot;:&quot;.main-content&quot;,&quot;min_height&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:0,&quot;sizes&quot;:[]},&quot;headings_by_tags&quot;:[&quot;h2&quot;,&quot;h3&quot;,&quot;h4&quot;,&quot;h5&quot;,&quot;h6&quot;],&quot;marker_view&quot;:&quot;numbers&quot;,&quot;minimize_box&quot;:&quot;yes&quot;,&quot;minimized_on&quot;:&quot;tablet&quot;,&quot;hierarchical_view&quot;:&quot;yes&quot;,&quot;min_height_tablet&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_mobile&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]}}\" data-widget_type=\"table-of-contents.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-toc__header\">\n\t\t\t\t\t\t<h4 class=\"elementor-toc__header-title\">\n\t\t\t\tTABLE OF CONTENTS\t\t\t<\/h4>\n\t\t\t\t\t\t\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--expand\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__2e80493\" aria-expanded=\"true\" aria-label=\"Open table of contents\"><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/div>\n\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--collapse\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__2e80493\" aria-expanded=\"true\" aria-label=\"Close table of contents\"><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<div id=\"elementor-toc__2e80493\" class=\"elementor-toc__body\">\n\t\t\t<div class=\"elementor-toc__spinner-container\">\n\t\t\t\t<svg class=\"elementor-toc__spinner eicon-animation-spin e-font-icon-svg e-eicon-loading\" aria-hidden=\"true\" viewBox=\"0 0 1000 1000\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M500 975V858C696 858 858 696 858 500S696 142 500 142 142 304 142 500H25C25 237 238 25 500 25S975 237 975 500 763 975 500 975Z\"><\/path><\/svg>\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5b8727a elementor-widget elementor-widget-heading\" data-id=\"5b8727a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">What Is Relative Refractive Index Difference (\u0394)?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-47d61a4 elementor-widget elementor-widget-text-editor\" data-id=\"47d61a4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">Relative Refractive Index Difference (\u0394) is a dimensionless parameter that expresses the difference between the refractive index of the fiber core and the cladding relative to the core refractive index. In optical fibers, \u0394 is typically less than 1%, yet this small difference is essential for guiding light through total internal reflection.<\/p><p>Despite its small value, \u0394 has a major influence on fiber performance. It affects how tightly light is confined within the core, the <a href=\"https:\/\/yfconnectivity.com\/what-is-unmerical-aperture\/\">numerical aperture (NA)<\/a> of the fiber, <a href=\"https:\/\/yfconnectivity.com\/fiber-optic-single-mode-vs-multimode\/\">the number of supported propagation modes<\/a>, and dispersion behavior. Larger values of \u0394 generally provide stronger light confinement and higher NA, while smaller values are commonly used in <a href=\"https:\/\/yfconnectivity.com\/fiber-optic-patch-cords\/\">single-mode fibers<\/a> to achieve better mode control and lower dispersion.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7a92a77 elementor-widget elementor-widget-image\" data-id=\"7a92a77\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference-1024x683.webp\" class=\"attachment-large size-large wp-image-8978\" alt=\"\" srcset=\"https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference-1024x683.webp 1024w, https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference-300x200.webp 300w, https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference-768x512.webp 768w, https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference-18x12.webp 18w, https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference-600x400.webp 600w, https:\/\/yfconnectivity.com\/wp-content\/uploads\/2026\/06\/relative-refractive-index-difference.webp 1200w\" sizes=\"(max-width: 1024px) 100vw, 1024px\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2fa9a02 elementor-widget elementor-widget-heading\" data-id=\"2fa9a02\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">What Does Relative Refractive Index Difference Actually Mean?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-de307ef elementor-widget elementor-widget-text-editor\" data-id=\"de307ef\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">At first glance, Relative Refractive Index Difference may sound like a complicated optical term. In reality, it simply describes how different the refractive indices of the fiber core and cladding are.<\/p><p class=\"isSelectedEnd\">A standard optical fiber consists of two layers:<\/p><ul data-spread=\"false\"><li>Core \u2013 the central region where light travels<\/li><li>Cladding \u2013 the outer layer surrounding the core<\/li><\/ul><p class=\"isSelectedEnd\">For light to remain trapped inside the core, the core must have a slightly higher refractive index than the cladding.<\/p><p class=\"isSelectedEnd\">For example:<\/p><ul data-spread=\"false\"><li>Core refractive index (n\u2081): 1.468<\/li><li>Cladding refractive index (n\u2082): 1.462<\/li><\/ul><p class=\"isSelectedEnd\">Although the difference appears extremely small, it is enough to create total internal reflection, which keeps light confined within the fiber.<\/p><p>Relative Refractive Index Difference is simply a convenient way to express this small difference as a percentage.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f73a459 elementor-widget elementor-widget-heading\" data-id=\"f73a459\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Relative Refractive Index vs. Refractive Index: What's the Difference?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-81b0cee elementor-widget elementor-widget-text-editor\" data-id=\"81b0cee\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">Many beginners confuse these two terms because they sound very similar.<\/p><p class=\"isSelectedEnd\">A refractive index describes the optical property of a material. It indicates how much light slows down when traveling through that material.<\/p><p class=\"isSelectedEnd\">Relative Refractive Index Difference, however, does not describe a material directly. Instead, it describes the relationship between two materials\u2014the fiber core and the cladding.<\/p><p class=\"isSelectedEnd\">Think of it this way:<\/p><ul data-spread=\"false\"><li>Refractive Index = Property of a material<\/li><li>Relative Refractive Index Difference = Difference between two materials<\/li><\/ul><p>In fiber optics, both values are important. The refractive indices determine how light behaves inside each layer, while \u0394 describes how effectively the fiber can guide that light.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ff9c75a elementor-widget elementor-widget-heading\" data-id=\"ff9c75a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">How Is \u0394 Calculated?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6c7b1be elementor-widget elementor-widget-text-editor\" data-id=\"6c7b1be\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">The Relative Refractive Index Difference is commonly calculated using the following equation:<\/p><p class=\"isSelectedEnd\">\u0394 = (n\u2081 \u2212 n\u2082) \/ n\u2081<\/p><p class=\"isSelectedEnd\">Where:<\/p><ul data-spread=\"false\"><li>n\u2081 = Core refractive index<\/li><li>n\u2082 = Cladding refractive index<\/li><\/ul><p class=\"isSelectedEnd\">Because the difference between n\u2081 and n\u2082 is extremely small, \u0394 is usually expressed as a percentage.<\/p><p>For most commercial optical fibers, the value typically falls between 0.3% and 1%.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c54d2ad elementor-widget elementor-widget-heading\" data-id=\"c54d2ad\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Why Is \u0394 Important in Optical Fibers?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-752b093 elementor-widget elementor-widget-text-editor\" data-id=\"752b093\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p data-start=\"4000\" data-end=\"4096\">Although \u0394 is usually less than 1%, it influences several key fiber characteristics.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e733660 elementor-widget elementor-widget-heading\" data-id=\"e733660\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">1. It Determines How Well Light Is Confined<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0c0623f elementor-widget elementor-widget-text-editor\" data-id=\"0c0623f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">The primary purpose of having different refractive indices is to keep light inside the core.<\/p><p class=\"isSelectedEnd\">A larger \u0394 means a greater refractive index difference between the core and cladding. This creates stronger light confinement and makes total internal reflection easier to achieve.<\/p><p>As a result, light remains more tightly guided within the fiber core.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-04d91c8 elementor-widget elementor-widget-heading\" data-id=\"04d91c8\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2. It Affects Numerical Aperture (NA)<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7a39ee4 elementor-widget elementor-widget-text-editor\" data-id=\"7a39ee4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\"><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u76f8\u5bf9\u6298\u5c04\u7387\u5dee\u4e0e\u6570\u503c\u5b54\u5f84\uff08NA\uff09\u5bc6\u5207\u76f8\u5173\u3002<\/span><\/span><\/p><p class=\"isSelectedEnd\"><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u4e00\u822c\u6765\u8bf4\uff1a<\/span><\/span><\/p><p class=\"isSelectedEnd\"><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u0394\u503c\u8d8a\u9ad8 \u2192 NA\u503c\u8d8a\u9ad8<\/span><\/span><\/p><p class=\"isSelectedEnd\"><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u66f4\u9ad8\u7684\u6570\u503c\u5b54\u5f84\u4f7f\u5149\u7ea4\u80fd\u591f\u63a5\u6536\u66f4\u5927\u8303\u56f4\u7684\u5165\u5c04\u89d2\u7684\u5149\uff0c\u4ece\u800c\u66f4\u5bb9\u6613\u5b9e\u73b0\u5149\u8026\u5408\u3002<\/span><\/span><\/p><p class=\"isSelectedEnd\"><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u8fd9\u4e5f\u662f\u591a\u6a21\u5149\u7ea4\u7684\u0394\u503c\u901a\u5e38\u6bd4\u5355\u6a21\u5149\u7ea4\u5927\u7684\u539f\u56e0\u4e4b\u4e00\u3002<\/span><\/span><\/p><p><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u5982\u679c\u60a8\u60f3\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u8fd9\u79cd\u5173\u7cfb\u7684\u4fe1\u606f\uff0c\u8bf7\u53c2\u9605\u6211\u4eec\u7684<\/span><\/span><a href=\"https:\/\/yfconnectivity.com\/what-is-unmerical-aperture\/\"><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u5149\u7ea4\u6570\u503c\u5b54\u5f84 (NA)<\/span><\/span><\/a><span dir=\"auto\" style=\"vertical-align: inherit;\"><span dir=\"auto\" style=\"vertical-align: inherit;\">\u6307\u5357\u3002<\/span><\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2f02a54 elementor-widget elementor-widget-heading\" data-id=\"2f02a54\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">3. It Influences Single-Mode and Multimode Fiber Design<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-734e792 elementor-widget elementor-widget-text-editor\" data-id=\"734e792\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">The value of \u0394 plays an important role in determining how light propagates through the fiber.<\/p><p class=\"isSelectedEnd\">Multimode fibers typically use a larger \u0394 because they are designed to support multiple propagation modes and benefit from a larger Numerical Aperture.<\/p><p class=\"isSelectedEnd\">Single-mode fibers generally use a smaller \u0394. This helps maintain tighter control over light propagation, reduces modal effects, and supports long-distance, high-bandwidth transmission.<\/p><p>For this reason, fiber designers carefully select \u0394 according to the intended application.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-274592f elementor-widget elementor-widget-heading\" data-id=\"274592f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Typical \u0394 Values in Optical Fibers<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-1895c7b elementor-widget elementor-widget-text-editor\" data-id=\"1895c7b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"flex max-w-full flex-col gap-4 grow\"><div class=\"min-h-8 text-message relative flex w-full flex-col items-end gap-2 text-start break-words whitespace-normal outline-none keyboard-focused:focus-ring [.text-message+&amp;]:mt-1\" dir=\"auto\" tabindex=\"0\" data-message-author-role=\"assistant\" data-message-id=\"d9a7702e-e0d3-4805-8cf8-d4125bee7702\" data-message-model-slug=\"gpt-5-5\" data-turn-start-message=\"true\"><div class=\"flex w-full flex-col gap-1 empty:hidden\"><div class=\"markdown prose dark:prose-invert w-full wrap-break-word light markdown-new-styling\"><p class=\"isSelectedEnd\">Different fiber types use different Relative Refractive Index Differences.<\/p><table><tbody><tr><th>Fiber Type<\/th><th>Typical \u0394<\/th><\/tr><tr><td>Single-Mode Fiber<\/td><td>0.3% \u2013 0.4%<\/td><\/tr><tr><td>Multimode Fiber<\/td><td>0.5% \u2013 1.0%<\/td><\/tr><\/tbody><\/table><p>While these numbers appear extremely small, even slight changes can significantly affect fiber performance.<\/p><\/div><\/div><\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4477848 elementor-widget elementor-widget-heading\" data-id=\"4477848\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">A Simple Analogy to Understand \u0394<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-615430d elementor-widget elementor-widget-text-editor\" data-id=\"615430d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"flex max-w-full flex-col gap-4 grow\"><div class=\"min-h-8 text-message relative flex w-full flex-col items-end gap-2 text-start break-words whitespace-normal outline-none keyboard-focused:focus-ring [.text-message+&amp;]:mt-1\" dir=\"auto\" tabindex=\"0\" data-message-author-role=\"assistant\" data-message-id=\"d9a7702e-e0d3-4805-8cf8-d4125bee7702\" data-message-model-slug=\"gpt-5-5\" data-turn-start-message=\"true\"><div class=\"flex w-full flex-col gap-1 empty:hidden\"><div class=\"markdown prose dark:prose-invert w-full wrap-break-word light markdown-new-styling\"><p class=\"isSelectedEnd\">Imagine a highway surrounded by guardrails.<\/p><p class=\"isSelectedEnd\">The cars represent light signals, while the guardrails represent the refractive index difference between the core and cladding.<\/p><p class=\"isSelectedEnd\">If the guardrails are strong and clearly defined, it becomes easier to keep vehicles moving in the correct direction.<\/p><p class=\"isSelectedEnd\">Similarly, a larger \u0394 creates stronger optical confinement, helping guide light through the fiber.<\/p><p>Of course, stronger confinement is not always better. Fiber designers must balance light confinement, Numerical Aperture, dispersion performance, and transmission requirements when selecting the appropriate \u0394 value.<\/p><\/div><\/div><\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8ab8e92 elementor-widget elementor-widget-heading\" data-id=\"8ab8e92\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Frequently Asked Questions<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-701feec elementor-widget elementor-widget-n-accordion\" data-id=\"701feec\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;default_state&quot;:&quot;expanded&quot;,&quot;max_items_expended&quot;:&quot;one&quot;,&quot;n_accordion_animation_duration&quot;:{&quot;unit&quot;:&quot;ms&quot;,&quot;size&quot;:400,&quot;sizes&quot;:[]}}\" data-widget_type=\"nested-accordion.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"e-n-accordion\" aria-label=\"Accordion. Open links with Enter or Space, close with Escape, and navigate with Arrow Keys\">\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-1170\" class=\"e-n-accordion-item\" open>\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"1\" tabindex=\"0\" aria-expanded=\"true\" aria-controls=\"e-n-accordion-item-1170\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Is a larger \u0394 always better? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-minus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h384c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-plus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H272V64c0-17.67-14.33-32-32-32h-32c-17.67 0-32 14.33-32 32v144H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h144v144c0 17.67 14.33 32 32 32h32c17.67 0 32-14.33 32-32V304h144c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" role=\"region\" aria-labelledby=\"e-n-accordion-item-1170\" class=\"elementor-element elementor-element-40a6522 e-con-full e-flex e-con e-child\" data-id=\"40a6522\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-d04153f elementor-widget elementor-widget-text-editor\" data-id=\"d04153f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">No. A larger \u0394 provides stronger light confinement and higher Numerical Aperture, but it may not be suitable for every application. Single-mode fibers often require smaller \u0394 values for better mode control.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-1171\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"2\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-1171\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> Is \u0394 measured in dB? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-minus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h384c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-plus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H272V64c0-17.67-14.33-32-32-32h-32c-17.67 0-32 14.33-32 32v144H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h144v144c0 17.67 14.33 32 32 32h32c17.67 0 32-14.33 32-32V304h144c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" role=\"region\" aria-labelledby=\"e-n-accordion-item-1171\" class=\"elementor-element elementor-element-8d63520 e-flex e-con-boxed e-con e-child\" data-id=\"8d63520\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-e75bb63 elementor-widget elementor-widget-text-editor\" data-id=\"e75bb63\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">No. Relative Refractive Index Difference is a dimensionless parameter and is typically expressed as a percentage.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-1172\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"3\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-1172\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> What is the typical \u0394 of single-mode fiber? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-minus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h384c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-plus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H272V64c0-17.67-14.33-32-32-32h-32c-17.67 0-32 14.33-32 32v144H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h144v144c0 17.67 14.33 32 32 32h32c17.67 0 32-14.33 32-32V304h144c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" role=\"region\" aria-labelledby=\"e-n-accordion-item-1172\" class=\"elementor-element elementor-element-79f1d74 e-con-full e-flex e-con e-child\" data-id=\"79f1d74\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-663d8bb elementor-widget elementor-widget-text-editor\" data-id=\"663d8bb\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p data-start=\"1438\" data-end=\"1536\">Most standard single-mode fibers have a \u0394 value between approximately 0.3% and 0.4%.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t<details id=\"e-n-accordion-item-1173\" class=\"e-n-accordion-item\" >\n\t\t\t\t<summary class=\"e-n-accordion-item-title\" data-accordion-index=\"4\" tabindex=\"-1\" aria-expanded=\"false\" aria-controls=\"e-n-accordion-item-1173\" >\n\t\t\t\t\t<span class='e-n-accordion-item-title-header'><div class=\"e-n-accordion-item-title-text\"> What is the relationship between \u0394 and Numerical Aperture? <\/div><\/span>\n\t\t\t\t\t\t\t<span class='e-n-accordion-item-title-icon'>\n\t\t\t<span class='e-opened' ><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-minus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h384c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t\t<span class='e-closed'><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-plus\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M416 208H272V64c0-17.67-14.33-32-32-32h-32c-17.67 0-32 14.33-32 32v144H32c-17.67 0-32 14.33-32 32v32c0 17.67 14.33 32 32 32h144v144c0 17.67 14.33 32 32 32h32c17.67 0 32-14.33 32-32V304h144c17.67 0 32-14.33 32-32v-32c0-17.67-14.33-32-32-32z\"><\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t<div data-particle_enable=\"false\" data-particle-mobile-disabled=\"false\" role=\"region\" aria-labelledby=\"e-n-accordion-item-1173\" class=\"elementor-element elementor-element-9df94c1 e-flex e-con-boxed e-con e-child\" data-id=\"9df94c1\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-532a77d elementor-widget elementor-widget-text-editor\" data-id=\"532a77d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p data-start=\"1916\" data-end=\"1932\">In general, a larger \u0394 results in a larger Numerical Aperture (NA), allowing the fiber to accept light over a wider range of input angles.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-08800f5 elementor-widget elementor-widget-heading\" data-id=\"08800f5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Conclusion<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-dab2e9e elementor-widget elementor-widget-text-editor\" data-id=\"dab2e9e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"isSelectedEnd\">Relative Refractive Index Difference (\u0394) is one of the most fundamental parameters in optical fiber design. Although it is typically less than 1%, it directly influences light confinement, Numerical Aperture, propagation modes, and dispersion behavior.<\/p><p>By controlling the refractive index difference between the core and cladding, fiber manufacturers can optimize optical fibers for different applications, from short-range multimode networks to long-distance single-mode transmission systems.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6e5cbd3 elementor-widget elementor-widget-heading\" data-id=\"6e5cbd3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Still Have Questions?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f919aef elementor-widget elementor-widget-text-editor\" data-id=\"f919aef\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>If you&#8217;re still unsure about something, feel free to reach out.<\/p><p>Want to explore more fiber optic terms? Head over to our blog section.<\/p><p>If the term you\u2019re looking for isn\u2019t covered yet, let me know \u2014 I\u2019ll add it to the priority list!<\/p><p>And lastly \u2014 if you\u2019re a telecom provider, network operator, or involved in fiber infrastructure development and looking for a reliable partner in fiber optic components \u2014 feel free to contact to us.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>What is Relative Refractive Index Difference (\u0394) in optical fiber? This guide explains the meaning of \u0394, how it is calculated, and why this small parameter plays a major role in light guidance, numerical aperture, mode propagation, and fiber design.<\/p>","protected":false},"author":1,"featured_media":8977,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[66],"tags":[],"class_list":["post-8974","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fiber-optic-glossary"],"acf":[],"_links":{"self":[{"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/posts\/8974","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/comments?post=8974"}],"version-history":[{"count":10,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/posts\/8974\/revisions"}],"predecessor-version":[{"id":9005,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/posts\/8974\/revisions\/9005"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/media\/8977"}],"wp:attachment":[{"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/media?parent=8974"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/categories?post=8974"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yfconnectivity.com\/fr\/wp-json\/wp\/v2\/tags?post=8974"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}