Recent Developments of Bend-insensitive and Ultra-bend-insensitive Fibers Fully Compliant with Both G.657.B and G.652.D ITU-T Recommendations Louis-Anne de Montmorillon 1 , David Boivin 1 , Lionel Provost 1 , Nelly Montaigne 2 , Frans Gooijer 3 , Eugen Aldea 3 , Jaap Jensma 3 , Pierre Sillard 1 1 Draka Communications, Marcoussis, France 2 Draka Communications, Douvrin, France 3 Draka Communications, Eindhoven, The Netherlands louis_anne.de_montmorillon@draka.com Abstract In this paper, we address our most recent works on all-solid bend-insensitive fibers (BIFs) and Ultra BIFs (UBIFs) made with the versatile PCVD process. The influence of connection losses on Multi-Path Interference (MPI) phenomenon is analyzed in these fibers. Notably, we demonstrate that compliance with G.652 specifications in term of cable cutoff wavelength ensures a very high tolerance to MPI in Fiber-To-The- Home networks. Then, we address the spliceability of such fibers using fusion and mechanical splicing. Reported statistics demonstrate excellent splicing performance for BIFs and UBIFs as well as an excellent backward compatibility with G.652 standard single-mode fiber. Finally, we illustrate the robustness of the all- solid single-trench-assisted concept by showing how simple controls of the PCVD process allows to tightly limit the distributions of fiber characteristics, especially the cable-cutoff- wavelength and of the macro-bend-loss distributions. Keywords: Single Mode Fibers; Bend Insensitive Fibers; ITU- T Recommendation G.657; Bend Losses; FTTH. 1. Introduction The emergence of Fiber-To-The-Home (FTTH) networks subject to harsher environments than Long-Haul (LH) networks has spurred the development of bend-insensitive fibers (BIFs) compliant with both G.657.B (see Table. 1) and G.652.D ITU-T recommendations. These fibers have profiles with standard central cores assisted by depressed index areas in the cladding (solid single trench [1-4], solid multiple trenches [5], air-hole trench [6,7]). Table 1. G.657.B ITU-T recommendation Attributes Cable Cutoff Max. MFD 1310nm Nominal range Tolerance Macrobending loss Radius (mm) 15 10 7.5 Number of turns 10 1 1 Max. at 1550nm (dB) 0.03 0.1 0.5 Max. at 1625nm (dB) 0.1 0.2 1.0 G.657B 1260 nm 6.3 - 9.5 μm ± 0.4 μm Using a simple and robust all-solid single-trench-assisted profile, we developed as early as 2006 the first BIF [1,2] compliant with both G.657.B and G.652.D ITU-T recommendations. In 2008, we introduced a G.652.D Ultra-BIF (UBIF) [3,4] that exhibits bend losses 10 times lower than G.657.B and <0.10dB/turn at 5mm bend radius at 1550nm. This fiber is a good candidate for component intra-connection and specialty applications. In this paper, we address our most recent works on these two fiber types. In section 2, we present our investigations on the Multi-Path Interference (MPI) phenomenon that has recently been identified as a new concern in FTTH deployments [3,8,9]. We will particularly focus on the impact of splices/connections losses on MPI and show that acceptable MPI levels can be obtained even in extremely degraded cases (>1dB/splices). In section 3, we detail our work on the spliceability assessment of these fibers, and cover fusion and mechanical splices. In section 4, we illustrate the robustness of our all-solid single-trench- assisted concept by showing how simple control of the versatile PCVD process allows to tightly limit the distributions of our BIF and UBIF characteristics. Table 2. Typical characteristics of all-solid single- trench-assisted BIF and UBIF Sample Cable Cutoff (nm) MFD (μm) at 1310 nm at 1550 nm λ0 (nm) Slope at λ0 (ps/nm²-km) PMD (ps/km 1/2 ) Loss (dB/km) at 1550 nm at 1625 nm Macrobending loss Wavelength (nm) = 1550 1625 1550 1625 (dB/turn) 5 mm radius 0.2 0.6 0.07 0.18 7.5 mm radius 0.1 0.2 0.03 0.09 10 mm radius 0.01 0.04 0.01 0.02 15 mm radius 0.001 0.005 0.001 0.005 0.201 0.190 0.02 0.02 1318 1316 0.090 0.089 BIF 1210 8.9 10.0 0.188 0.199 UBIF 1230 8.75 9.85 2. MPI Investigations MPI is one important parameter that has rarely been addressed up to now. Known for a long time in LH networks, it is a well-known way to estimate the impact of a few-mode behavior when the system is operated lower or close to the cutoff wavelength. MPI is International Wire & Cable Symposium 270 Proceedings of the 58th IWCS/IICIT