What is the Bend Loss Sensitivity of a DTG®?

In general, bending losses in the DTG-LBL-1550 can be considered to be negligibly small. To illustrate this, some measured bending-induced optical losses are presented in the table below. As can be seen, the attenuation per winding for millimeter-sized radii is less than 1 dB.

Table: Bending loss of DTG-LBL-1550 fiber


The limiting factor for the operational minimal bending radius will rather be governed by the bending-induced strain in the fiber glass. Coiling an optical fiber over a small bending radius gives rise to bending strain in the fiber.  For large strain values, it can lead to a damage in the optical fiber or even breakage. The strain due to bending is largest at the optical fiber surface. The surface strain can be calculated as a function of the bending radius and optical fiber diameter. The figure below shows the surface strain as function of the bending radius for an 80µm and a 125µm diameter optical fiber.

Figure: Surface strain as function of the bending radius for a fiber cladding of 80µm diameter and a fiber cladding of 125µm diameter fiber.

In order to prevent fiber breakage on the long term, the strain should be as small as possible. As can be observed, the smaller the fiber diameter, the lower the surface strain for an identical bending radius. In case smaller bending radii are needed, it is recommended to use smaller fiber diameters.

For more information, please contact us at info@fbgs.com


Sign up for newsletter

Contact us

* These fields are required.

How we use your information

We are committed to respecting your privacy and protecting your personal information and will always treat it with the upmost care. You can find out how we handle your data and all the ways we use it to provide you with a better service in our Privacy Statement.

By submitting this form, you consent to the use of your data in accordance with our Privacy Statement.


FBGS Technologies GmbH
Franz Loewen Straße 3
D-07745 Jena


FBGS International NV
Bell Telephonelaan 2H
B-2440 Geel


Suzhou X2 Electronic Technology Co Ltd
Room No. 2003, Building 38, No. 60 Weixin Road, Suzhou Industrial Park
215122 Suzhou, Jiangsu China