G.657B bend-insensitive single-mode fibers, completely compliant to G.652D

Inhalt:
The publication of ITU-T recommendation G.657 in 2006 supported the strong interest by operators and industry for bend-insensitive Single Mode Fibers (SMF) in particular for Fiber-to-the-Home deployment. Due to the dense distribution, the limited space and the many manipulations in the access network, fiber and cable applied here need different optimization compared to use in a general transport network. Recommendation G.657 (2006) defines two categories A & B mainly differing in bend-loss performances, with the A-category showing slightly improved bending performance as a subset of legacy G.652D. The G.657 B-category specifies more tight fiber bend-loss levels. This category represents a wider range of different designs showing nominal mode-field diameters (MFD) ranging from 6.3 µm up to 9.5 µm. Because of this large MFD range the entire G.657 B-category is not G.652D compatible, in particular caused by the low MFD fibers. In this paper we will highlight the world’s first commercially available G.657B fiber totally G.652D compliant, based on a solid-glass, trench-assisted design. Further optimizing this design, even a fiber with “beyond G.657 B-class” performance has been developed with tight specification at 5mm radius of maximum 0.1 dB/turn at 1550nm. We will highlight important aspects like splice compatibility of trench-assisted G.657B fibers to G.652D fibers.