FAQ related to Optical Fibers

The minimum allowable bend radius of optical fibers is generally 30 mm. Therefore, bending an optical fiber to a radius of less than 30 mm should be avoided. Sumitomo Electric offers bend insensitive fiber products such as PureBand™-Plus, PureBand™-R, PureBand™-R[LL], and PureAccess™, which have a minimum allowable bend radius of 10 mm. Additionally, Sumitomo Electric has developed a 7.5 mm bend-radius SM fiber called PureAccess™[A2], which represents an even smaller bend radius.

Please refer the following illustrations.

Yes. If you are considering exporting our optical fibers or some products incorporating those fibers to EU countries, you can download the RoHS certificate of conformity for the fibers from following link.

If you would like to request RoHS certificate for other products or materials besides the fibers, or other certificate besides RoHS, please contact our representative directly by clicking [Contact us] button below this page.

Yes. PureAdvance™ series fibers can be spliced with standard fusion splicers. In addition, results can be further optimized if your splicer offers a G.654.E splicing program.

The typical structure of optical fiber is illustrated in the following figure.
Optical fibers are composed of two glass layers known as the core and the cladding, which are coated with protective acrylate layers. For this protective layer, Sumitomo Electric utilizes a dual-layer acrylate coating structure. The precisely controlled coating diameters and the exceptional mechanical performance of our fibers, which contribute to high product reliability, are highly regarded by customers in the device and cable industries.
The typical coating diameter of optical fiber is 250 µm. In addition, Sumitomo Electric has developed fiber products with 200 µm coating diameters by leveraging our fiber coating technologies. A 180 µm coating diameter is also available for the PureAccess™ series, which complies with Recommendation ITU-T G.657.A1 and A2.
To find out more, please visit our Optical Fibers website.

Several types of optical fibers are recommended by ITU-T. Recommendations are as follows.

ITU-T Recommendation	Type	Category	Transmission Wavelength Band	Our Products
G.651.1	Multi-mode Fiber (MMF)	Graded-index MMF	850 and/or 1300 nm region	-
G.652	Single-mode Fiber (SMF)	Standard SMF	1260-1625 nm	PureBand series PureAccess series
G.653		Dispersion Shifted Fiber (DSF)	1550 nm region	-
G.654		Cutoff Shifted Fiber	1530-1625 nm	PureAdvance series Z Fiber series
G.655		Non-Zero Dispersion Shifted Fiber (NZDSF)	1460-1565 nm	-
G.656		Wideband NZDSF	1460-1625 nm	-
G.657		Bending-Loss Insensitive SMF	1260-1625 nm	PureBand-R PureBand-Plus PureAccess series

(ITU-T: International Telecommunication Union – Telecommunication Standardization Sector)

Sumitomo Electric’s product lineup offers a wide range of optical fibers complying with various ITU-T Recommendations e.g. G.652, G.657, and G.654.

ITU-T G.652:
ITU-T G.652 SMFs are the most widely used optical fiber in the world. G.652.B is the base category of G.652. G.652.D has similar characteristics with G.652.B, but also has reduced water peak attenuation around 1380 nm to allow transmissions in the extended wavelength of 1260-1625 nm.
Sumitomo Electric’s standard SMFs, PureBand series and PureAccess series are compliant with ITU-T G.652.D.

ITU-T G.657:
ITU-T G.657 fibers have improved bending loss performances compared with ITU-T G.652 fibers. These fibers can be used for many applications where the space is limited and bend optimized cabling is advantageous, e.g., datacenter, FTTH, access, and metro networks.
Subcategories G.657.A1 and G.657.A2 are appropriate for a minimum bending radius of 10 and 7.5 mm, respectively. These fibers are also upward compatible with ITU-T G.652.
Sumitomo Electric’s bend insensitive fibers, PureBand-R, PureBand-Plus and PureAccess series are compliant with ITU-T G.657.A1 or G.657.A2.

ITU-T G.654:
ITU-T G.654 fibers are loss-minimized and cut-off shifted at a 1550 nm wavelength region, and optimized for use in the 1530-1625 nm region. The very low loss G.654 fibers can be used for long distance transmission applications, including submarine cable systems and long-haul terrestrial systems.
G.654.B has a large MFD compared to G.654.A and G.654.C, and can be applied to long distance and large capacity WDM transmission systems. G.654.D has a yet larger MFD to further improve the optical signal to noise ratio (OSNR) characteristics. G.654.E is optimized for high bit-rate coherent transmission in terrestrial long-haul systems.
Sumitomo Electric’s ultra-low loss submarine fibers, Z Fiber series is compliant with ITU-T G.654.B, G.654.C, or G.654.D.
Sumitomo Electric’s ultra-low loss terrestrial long-haul fibers, PureAdvance series is compliant with ITU-T G.654.E.    

Optical fibers can be connected through either fusion or mechanical splicing, which provide a permanent connection, or by using connectors that allow for repeated disconnection. Optical connectors are primarily utilized at junctions where switching is necessary for operational and maintenance purposes.
To learn more, please visit our Fusion splicer and Connector websites.