{"id":1164,"date":"2026-09-19T00:06:32","date_gmt":"2026-09-19T00:06:32","guid":{"rendered":"https:\/\/www.fenxifiber.com\/plc-vs-fbt-splitter\/"},"modified":"2026-09-19T00:06:32","modified_gmt":"2026-09-19T00:06:32","slug":"plc-vs-fbt-splitter","status":"publish","type":"post","link":"https:\/\/www.fenxifiber.com\/pt\/plc-vs-fbt-splitter\/","title":{"rendered":"Divisor PLC x Divisor FBT: Guia de sele\u00e7\u00e3o para PON | Fenxi"},"content":{"rendered":"

Splitter choice decides how many subscribers one OLT port can serve and how much link margin survives at the far end. Buy the wrong technology and the loss you measured at 25 °C drifts out of spec in a roadside cabinet by August. This guide compares PLC and FBT splitters on the parameters that show up in an acceptance test — insertion loss, uniformity, wavelength range, temperature behavior, package formats and cost per port — so procurement and engineering teams can specify from evidence instead of habit.<\/p>\n

\"fiber<\/p>\n

Two Ways to Split Light<\/h2>\n

A PLC (Planar Lightwave Circuit) splitter is built on a silica wafer. Photolithography etches a tree of Y-branch waveguides into the chip, and the split ratio is fixed by the mask, not by a production operator. Every unit from the same wafer splits within a tight tolerance band, and the response stays flat from 1260 to 1650 nm.<\/p>\n

An FBT (Fused Biconical Taper) splitter is made the older way: two or more bare fibers are twisted, fused under heat and drawn into a biconical taper so light couples between cores. The taper length sets the ratio during production. That process is cheap at low split counts and permits unequal ratios such as 90\/10 or 70\/30, which PLC chips cannot offer, but the coupling is wavelength-dependent and the fused joint is sensitive to temperature and mechanical stress.<\/p>\n

The manufacturing difference explains every line in the comparison that follows. A waveguide defined by a photomask cannot drift toward one output port the way a hand-drawn taper can, and a wafer yields thousands of near-identical devices, which is why high-count PLC pricing falls as volumes rise. FBT remains in production because a fused coupler at 1×2 costs less to build than a lithographed chip, and because unequal ratios have no PLC equivalent.<\/p>\n

Head-to-Head Specification Comparison<\/h2>\n

The table below lines up the parameters that matter on a purchase order. Values follow the ranges published in GR-1209-CORE and GR-1221-CORE for PLC devices and typical manufacturer datasheets for FBT couplers.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
Par\u00e2metro<\/th>\nPLC Splitter<\/th>\nFBT Splitter<\/th>\n<\/tr>\n<\/thead>\n
Constru\u00e7\u00e3o<\/td>\nWaveguide chip on silica wafer<\/td>\nFused and drawn fiber taper<\/td>\n<\/tr>\n
Wavelength range<\/td>\n1260–1650 nm, flat<\/td>\nOptimized near 1310 \/ 1490 \/ 1550 nm<\/td>\n<\/tr>\n
Split ratios<\/td>\n1×2 to 1×64, equal only<\/td>\n1×2 to 1×8 practical; unequal ratios available<\/td>\n<\/tr>\n
Port uniformity<\/td>\n≤ 1.5 dB at 1×32<\/td>\nWorse at high counts; drifts with temperature<\/td>\n<\/tr>\n
Temperatura operacional<\/td>\n−40 to +85 °C<\/td>\n−5 to +75 °C typical<\/td>\n<\/tr>\n
Polarization dependent loss<\/td>\n≤ 0.3 dB<\/td>\n≤ 0.3 dB at design wavelength<\/td>\n<\/tr>\n
Cost at 1×2 \/ 1×4<\/td>\nHigher<\/td>\nInferior<\/td>\n<\/tr>\n
Cost per port at 1×32<\/td>\nInferior<\/td>\nHigher once cascading is counted<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Insertion Loss and Uniformity by Split Ratio<\/h2>\n

Both technologies obey the same physics — each split costs about 3.5 dB of theoretical loss plus excess loss — but only PLC holds the tolerance at scale. The values below reflect GPON planning practice under ITU-T G.984 and are the numbers to load into a loss budget before you sign a contract, as covered in our insertion loss budget walkthrough.<\/p>\n

\"SC\/APC<\/p>\n\n\n\n\n\n\n\n\n\n\n
Split ratio<\/th>\nMax insertion loss (dB)<\/th>\nUniformity (dB)<\/th>\nPractical technology<\/th>\n<\/tr>\n<\/thead>\n
1×2<\/td>\n≤ 4.1<\/td>\n≤ 0.8<\/td>\nFBT or PLC<\/td>\n<\/tr>\n
1×4<\/td>\n≤ 7.4<\/td>\n≤ 1.0<\/td>\nFBT or PLC<\/td>\n<\/tr>\n
1×8<\/td>\n≤ 10.7<\/td>\n≤ 1.2<\/td>\nPLC preferred<\/td>\n<\/tr>\n
1×16<\/td>\n≤ 14.0<\/td>\n≤ 1.5<\/td>\nPLC<\/td>\n<\/tr>\n
1×32<\/td>\n≤ 17.2<\/td>\n≤ 1.8<\/td>\nPLC only<\/td>\n<\/tr>\n
1×64<\/td>\n≤ 20.8<\/td>\n≤ 2.5<\/td>\nPLC only<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

An FBT device can reach 1×16 or 1×32 only by cascading several fused tapers inside one package. Cascading stacks the uniformity errors of every stage, so the worst output port — not the average port — decides whether the farthest subscriber stays online. Quote worst-port loss, and hold suppliers to maximum values, not catalog typicals.<\/p>\n

Wavelength Range and Triple-Play Services<\/h2>\n

GPON carries 1490 nm downstream, 1310 nm upstream and often a 1550 nm RF video overlay on the same tree; XGS-PON adds 1577 nm. A splitter that performs at its design wavelength but rolls off elsewhere quietly breaks one of those services. Because PLC waveguides split by geometry, the loss stays flat across the whole 1260–1650 nm window, so the same device serves a GPON build today and an XGS-PON or WDM overlay later without replacement. Requirements for PON reach and classes are set by ITU-T G.984<\/a>, and the underlying component test methods sit with IEC Webstore<\/a>.<\/p>\n

FBT couplers are tuned to one or two windows. The tap that measured 3.6 dB at 1310 nm can show several tenths more at 1550 nm, which is exactly where the video overlay lives. If a legacy design already uses FBT taps for monitoring, keep them on single-wavelength segments and specify PLC for the distribution tree.<\/p>\n

Wavelength flatness also protects the upgrade path. Operators across Southeast Asia and Latin America are moving from GPON to XGS-PON on the same outside plant, re-using splitters and closures while swapping OLT and ONT line cards. A splitter bank that only meets spec at three spot wavelengths forces a truck roll per home when that day comes. Specifying full-band PLC today is the difference between a card swap and a rebuild.<\/p>\n

Temperature Stability and Outdoor Cabinets<\/h2>\n

Field reports from hot-climate rollouts show FBT insertion loss drifting well above datasheet values once cabinet interiors pass 45 °C. The fused taper moves with thermal cycling; the lithographed waveguide does not. For aerial closures, pedestals and street cabinets — the normal home of an FTTH splitter — ask for GR-1209-CORE and GR-1221-CORE test data covering the −40 to +85 °C range, and for a sealed ABS or LGX package with the fiber routing protected inside a termination box rather than loose in the cabinet. For the mathematics behind those margins, the Refer\u00eancia ao or\u00e7amento de perdas da FOA<\/a> e o Guia de or\u00e7amento de perdas da Fluke Networks<\/a> both walk through worked examples.<\/p>\n

Humidity and vibration belong in the same conversation. Coastal and monsoon markets add condensation cycles to the thermal cycles, and every cable tie that presses on a bare fused taper is a long-term loss change waiting to happen. Confirm that the package routes pigtails around the housing walls with bend radii above 15 mm and that the test report includes damp heat, not just dry heat.<\/p>\n

\"SC\/APC<\/p>\n

Package Formats and Mounting<\/h2>\n

Both technologies ship in similar mechanical formats, but availability differs. PLC splitters come as bare-fiber modules for splicing into closures, LGX cassette and blockless formats for racks, and ABS boxes with SC\/APC or LC\/APC adapters for cabinet DIN rails and ODF shelves. FBT is mostly found as a boxed or fan-in\/fan-out unit at low counts, or as a welded module inside a CATV node. When you plan ports, check adapter polish and pigtail length together — SC\/APC 8° is the GPON default because angled polish keeps return loss below −55 dB at 1550 nm. Rack-level planning belongs in an ODF frame<\/a>, while drop-side splitting usually lands in a caixa de termina\u00e7\u00e3o de fibra<\/a> near the subscriber cluster.<\/p>\n

\"2x2<\/p>\n

Unit Price vs Cost per Port<\/h2>\n

At 1×2 and 1×4, FBT wins on price, and for a lab tap or an OTDR monitor port that is the right buy. From 1×8 upward the math reverses. A cascaded FBT 1×32 costs more per port than a single-chip PLC 1×32, carries worse uniformity, and — in uncontrolled temperatures — fails more often, which adds truck rolls. Over the service life of an access network, the cheapest line item is rarely the cheapest component. Compare quotations on cost per delivered port at worst-case loss, not on unit price. Connector and adapter choices follow the same evidence-driven logic described by TIA Online<\/a> standards for premises cabling.<\/p>\n

Put numbers on it. If a 1×32 FBT bank saves two dollars per unit but needs one extra service visit per hundred units across five years, at a typical eighty-dollar roll-out cost per visit the saving is gone before year two. Procurement teams that model replacement labor alongside unit price routinely find PLC the cheaper high-count option even where the invoice line looks equal.<\/p>\n

Splitter Selection Decision Tree<\/h2>\n

Work through the questions in order. The first answer that matches your project fixes the technology.<\/p>\n\n\n\n\n\n\n\n\n\n
Question<\/th>\nIf yes<\/th>\nIf no<\/th>\n<\/tr>\n<\/thead>\n
Is the split ≥ 1×8?<\/td>\nSpecify PLC<\/td>\nGo to next question<\/td>\n<\/tr>\n
Does the network carry ≥ 3 wavelengths (GPON triple-play, XGS-PON, WDM overlay)?<\/td>\nSpecify PLC<\/td>\nGo to next question<\/td>\n<\/tr>\n
Is the mounting environment uncontrolled (outdoor cabinet, aerial, pedestal)?<\/td>\nSpecify PLC<\/td>\nGo to next question<\/td>\n<\/tr>\n
Do you need an unequal ratio (90\/10 tap, 70\/30 monitor)?<\/td>\nSpecify FBT<\/td>\nGo to next question<\/td>\n<\/tr>\n
Is it a low-count indoor tap or lab unit where unit price rules?<\/td>\nFBT is acceptable<\/td>\nSpecify PLC as the safe default<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Send your OLT class, split plan and fiber lengths with your RFQ. A supplier who sizes the splitter against your power budget — B+ 28 dB, C+ 32 dB, C++ 35 dB — before quoting is a supplier worth keeping. The fiber optic splitter catalogue<\/a> covers both technologies, and the PLC splitter specification checklist<\/a> lists the datasheet lines to demand for either one. For the arithmetic that converts worst-port loss into a pass or fail at the ONT, see c\u00e1lculo do or\u00e7amento de perda de inser\u00e7\u00e3o<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"

Compara\u00e7\u00e3o entre divisores PLC e FBT em termos de perda, faixa de comprimento de onda, rela\u00e7\u00e3o de divis\u00e3o e desvio de temperatura, com uma \u00e1rvore de decis\u00e3o para sele\u00e7\u00e3o em redes GPON e FTTH. Solicite um or\u00e7amento \u00e0 Fenxi.<\/p>","protected":false},"author":1,"featured_media":628,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1164","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"_links":{"self":[{"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/posts\/1164","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/comments?post=1164"}],"version-history":[{"count":0,"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/posts\/1164\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/media\/628"}],"wp:attachment":[{"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/media?parent=1164"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/categories?post=1164"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fenxifiber.com\/pt\/wp-json\/wp\/v2\/tags?post=1164"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}