Overview
The BWNFiber 70/30 fiber coupler is a fused biconical taper (FBT) 1×3 unequal-split coupler: the larger share of one singlemode input continues down the through (signal) leg, while the smaller share is diverted to a tap leg for monitoring or test access. Two standard models — 70:30 and 90:10 — ship with SC/APC connectors, 3.0mm jacketed 3m leads, and published per-leg insertion loss.
Buy for permanent monitoring points, PON test access, CATV/RF-overlay taps, and lab test benches. Need three equal outputs instead? Use the even-split 1×3 pages below. Custom ratios from 50/50 down to 1/99, other connectors, and other lead lengths are available via the FBT splitter category.
Key Features
- Two unequal ratios as standard models: 70:30 and 90:10 cover the most common tap depths, so ratio selection is an engineering decision, not a custom-order project.
- Published per-leg loss: 70:30 — through ≤1.9 dB, tap 4.6–5.7 dB; 90:10 — through ≤0.63 dB, tap 9.3–11.0 dB (connectors excluded).
- Low excess loss, low PDL, high directivity: 0.1 dB typical excess loss, ≤0.15 dB max PDL, ≥55 dB directivity.
- SC/APC interfaces: return loss ≥55 dB per the singlemode FBT tables — suited to GPON/FTTH and RF-video links where reflectance degrades the signal.
- Ruggedized 3.0mm × 3m leads, steel-tube package: protected routing in distribution boxes and splice closures; 0.9/2.0mm jackets available.
- Four wavelength windows: 1310±40, 1550±40, dual 1310/1550, or triple 1310/1550/1490 nm — one device can pass GPON upstream, downstream, and 1550nm video overlay.
Specifications
Both models share the same package and interfaces; they differ only in split ratio and per-leg loss. Values come from the singlemode FBT coupling-ratio table, shown in each model’s through:tap orientation — the 70:30 model corresponds to the 30/70 row, the 90:10 model to the 10/90 row. All optical data excludes connectors.
| Model | Split Ratio (Through:Tap) | Through / Signal Leg IL (dB) | Tap Leg IL (dB) | Connector | Jacket | Lead Length |
|---|
| Model 1 | 70:30 | ≤1.9 | 4.6–5.7 | SC/APC | 3.0mm | 3m |
| Model 2 | 90:10 | ≤0.63 | 9.3–11.0 | SC/APC | 3.0mm | 3m |
| Excess Loss (Typical) | 0.1 dB |
| PDL (Max) | 0.15 dB |
| Directivity | ≥55 dB |
| Return Loss (per singlemode FBT tables) | ≥55 dB |
| Operating Wavelength | 1310±40, 1550±40, 1310/1550±40, 1310/1550/1490±40 nm, or custom wavelength |
| Port Configuration | 1×2 or 1×N (this page: 1×3) |
| Fiber Mode Options | G652D, G657A1, G657A2 |
| Jacket / Lead Options | 0.9mm, 2.0mm, 3.0mm; standard 1m or customized (these two models: 3m) |
Note: All the data above does not include connectors.
For custom-ratio orders, the full singlemode FBT coupling-ratio reference applies (verbatim from the product specification table):
| Coupling Ratio | Tap (Insertion Loss dB) | Signal (Insertion Loss dB) |
|---|
| 50/50 | 2.8–3.6 | ≤3.6 |
| 45/55 | 3.3–3.9 | ≤3.0 |
| 40/60 | 3.8–4.5 | ≤2.6 |
| 35/65 | 4.2–5.0 | ≤2.2 |
| 30/70 | 4.6–5.7 | ≤1.9 |
| 25/75 | 5.8–6.7 | ≤1.6 |
| 20/80 | 6.7–7.6 | ≤1.2 |
| 15/85 | 7.8–9.0 | ≤0.98 |
| 10/90 | 9.3–11.0 | ≤0.63 |
| 5/95 | 12.4–14.0 | ≤0.41 |
| 1/99 | 18.6–21.0 | ≤0.25 |
Note: All the data above does not include connectors. For even-split loss values across 1×2 to 1×64, use the splitter loss chart (1×2 to 1×64).
Connectors, Fiber Types & Compatibility
Both stocked models terminate in SC/APC; SC, LC, FC, and ST in APC or UPC polish are built on request, with G652D, G657A1, or G657A2 singlemode fiber. The 3.0mm leads route like standard patch cords, so the coupler drops into fiber distribution boxes, splice closures, and wall-mount enclosures without bare-fiber handling. Multimode unequal builds sit on the LC/UPC SM & MM page linked below.
Applications
- Permanent network monitoring: the tap leg feeds a power meter or monitoring probe while the through leg carries live traffic; the 90:10 model costs the link ≤0.63 dB.
- Test access on PON segments: OTDRs and test sets connect at the tap leg without breaking the through path; the triple-window build passes 1310/1490/1550nm.
- GPON / FTTH / FTTx distribution: unequal taps add monitoring or a low-priority branch — see FTTx supporting products for the enclosures these install into.
- CATV and RF-overlay feeds: a small tap share typically feeds a monitoring receiver or local drop while the through leg carries the forward RF signal; SC/APC keeps reflectance low on video-grade links.
- Telecom LAN/WAN and metro: the 70:30 through leg keeps ≤1.9 dB loss where an even 1×3 split costs every output up to 5.6 dB.
How to Choose: Ratio, Window, Connector, Jacket
1. Confirm you need an unequal tap, not an even split. Equal drops point to an even-split 1×3 (linked below). One output that must stay strong while another feeds monitoring, test gear, or a low-priority branch points to this page.
2. Pick the ratio from the link budget, not habit. Through leg: ≤0.63 dB (90:10) or ≤1.9 dB (70:30). Tap leg: 9.3–11.0 dB or 4.6–5.7 dB. Tight through budgets point to 90:10 if the monitoring receiver tolerates roughly 10 dB less power; long monitoring runs or less sensitive receivers point to 70:30. Shallower taps (5/95, 1/99) exist for links that can spare almost nothing.
3. Match the wavelength window to the signal under watch. Single-window 1310 or 1550; dual 1310/1550 for mixed plants; triple 1310/1490/1550 where GPON and RF video share the fiber.
4. Keep SC/APC unless your plant says otherwise. APC polish supports the ≥55 dB return loss in these tables; UPC, LC, FC, and ST builds are orderable.
5. Specify the mechanical build. State jacket (0.9/2.0/3.0mm), lead length (3m standard here), and — on 1×3 builds — which fibers are through and which are tap, so port allocation is confirmed before production.
Even-Split 1×3 vs This Unequal 1×3
This page covers unequal (tap) configurations only. Neighboring configurations each have their own page:
Testing & Quality Control
Optical performance is verified against the parameters in the specification table; compliance with Telcordia GR-1209-CORE and GR-1221-CORE is stated per BWNFiber product documentation.
Packaging & Ordering Information
These two models ship as steel-tube FBT couplers with 3.0mm × 3m SC/APC leads. Custom ratios, connectors, jackets, and lead lengths are built to order. For the datasheet and the latest Fiber Optic & FTTx / ODN catalog, contact the BWNFiber team.
Request a Quote
To price either model, include six parameters:
- Split ratio and orientation — 70:30 or 90:10, which leg is through
- Port configuration — 1×3, with the required tap/through allocation
- Connector and polish — SC/APC standard; LC/FC/ST and UPC optional
- Wavelength window — 1310, 1550, dual, or triple 1310/1490/1550
- Jacket and lead length — 3.0mm × 3m standard; 0.9/2.0mm and custom lengths available
- Quantity and application — monitoring, test access, CATV, or distribution
Send the list through the inquiry form or contact our team for datasheet, pricing, and ordering support.
