Corning ClearCurve ZBL Bare Optical Fiber
ClearCurve ZBL is the tightest bend-radius single-mode fiber Corning makes — G.657.B3 rated for 1-turn bends at 5 mm radius while remaining optically compatible with the SMF-28 and SMF-28e+ installed base. ZBL stands for zero bend loss, reflecting the near-zero additional attenuation at bend radii that would severely attenuate any other single-mode fiber.
- ITU-T standard
- G.657.B3
- Mode field diameter
- 9.05 ± 0.4 µm @ 1310 nm
- Attenuation @ 1310 nm
- ≤ 0.35 dB/km
- Attenuation @ 1550 nm
- ≤ 0.20 dB/km
G.657.B3 is the most demanding ITU-T bend performance class. It requires that 1 turn at a 5 mm radius adds less than 0.15 dB at 1550 nm. Standard G.652.D fiber fails severely at that radius. ZBL meets the spec while maintaining a 9.05 µm mode field diameter that splices to the installed SMF-28e+ base without a mode-field mismatch penalty.
The applications are anywhere fiber gets physically abused: stapled drop cables on building exteriors, routing through conduit bends that approach 90 degrees, MDU installations where installers cannot control bend radii, any closure or enclosure where the fiber must wrap around hardware. ZBL provides insurance that a tight bend that would break an ordinary drop fiber is simply a low-loss event on this one.
ZBL is not necessary for controlled indoor or outside plant installations where bend radii are managed. It is the right choice when the fiber will be handled by non-specialists or routed through hardware designed for copper.
Specifications
| ITU-T standard | G.657.B3 |
|---|---|
| Mode field diameter | 9.05 ± 0.4 µm @ 1310 nm |
| Attenuation @ 1310 nm | ≤ 0.35 dB/km |
| Attenuation @ 1550 nm | ≤ 0.20 dB/km |
| Bend: 1 turn @ 5 mm radius | ≤ 0.15 dB added @ 1550 nm |
| G.652.D compatibility | Yes — splices to SMF-28e+ installed base |
Typical Applications
- FTTH drop cables where stapling or tight routing is expected
- MDU in-building drops routed through walls and conduit by non-specialists
- Any installation where the fiber will experience sub-10 mm bend radii
- Closure and enclosure routing around hardware
Why Order Corning Fiber from Aumictech?
We source directly from the Corning authorized channel. Every spool ships with documentation, including reel ID and fiber code.
0.5 km to 1,000 km on a single order. Mix lengths across spools. Choose FC, SC, or LC connectors per spool end, or leave ends bare.
Certificate of compliance and OTDR test data available on request. Required for carrier acceptance testing and network documentation.
Continental US next-day and two-day air available. International shipping on request. Most orders confirmed within one business day.
Frequently Asked Questions
Does ClearCurve ZBL require special connectors or splicing technique?
No. ZBL uses standard 125 µm cladding and a 9.05 µm MFD that is within splicing tolerances for SMF-28e+ compatible equipment. Standard fusion splicers and field connectors work without any modification. The bend performance improvement comes from the fiber design, not from any hardware change.
Can ClearCurve ZBL be deployed in the same network as SMF-28 Ultra?
Yes. The 9.05 µm MFD of ZBL and the 9.2 µm MFD of SMF-28 Ultra produce a splice loss that is typically 0.05-0.10 dB on a core-alignment splicer, which is acceptable for virtually any FTTH or campus application. In a span where ZBL is used only for the last few hundred meters of drop cable and SMF-28 Ultra for the feeder, the total splice loss contribution is negligible.