Summary
International Symposium on Extremely Advanced Transmission Technologies
2019
Session Number:P
Session:
Number:P-06
Behavior of Inter-core Crosstalk against Disturbance in Heterogeneous Multi-core Fibers
Yoshimichi Amma, Katsuhiro Takenaga, Takeshi Fujisawa, Kunimasa Saitoh, Masanori Koshiba, Kazuhiko Aikawa,
pp.-
Publication Date:2019/5/29
Online ISSN:2188-5079
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Summary:
"Un-coupled multi-core fibers (MCFs) are expected as media to overcome the capacity limit of optical communication system using conventional single-mode fibers. To realize long-haul transmission system with MCFs, reduction of inter-core crosstalk (IC-XT) is one of the most important issues. Heterogeneous MCFs (Hetero-MCFs), in which the effective refractive index (neff) of each core is different from that of the neighboring ones, can drastically decrease IC-XT [1]. In a Hetero-MCF, correlation length d is the dominant factor of IC-XT at the bending radius R of more than Rpk which is a threshold bending radius. In some previous reports, values of d have been estimated from experimental results, but there are large differences among the estimated values from 50 mm to 100 m [2,3]. In this paper, we report behavior of IC-XT against disturbance which is winding tension on a spool T in three types of Hetero-MCFs, which are called heterogeneous two-core fiber A (2CF-A), B (2CF-B) and 30-core fiber (30CF) shown in Fig.1. These fibers have nearly same core characteristics, core pitch and Rpk. 2CF-A and 2CF-B have different cladding diameters of 134 ?m and 229 ?m, and 2CF-B and 30CF have different core arrangements, respectively. Measured IC-XT which is converted to after 10-km transmission with various T is shown in Fig.2. It's confirmed that IC-XTs in all of the three Hetero-MCFs increase with the increase of T. This result indicates that micro bending caused by large lateral pressure by T makes decrease of d. Figure 2 also shows the IC-XT value and variation of 2CF-A are larger than those of 2CF-B. This indicates that the large cladding diameter suppresses the decrease of d due to strong resistance against micro bending. When comparing 2CF-B with 30CF, 10-km IC-XTs of the both fibers are nearly same at small T of less than about 130 gf. From the result, it's assumed that the core arrangement in Hetero-MCFs doesn't affect their correlation length. However, IC-XT difference becomes large at T of more than 250 gf. We presume the difference is caused by large difference of the number of winding layer on spool. In the measurement, the number of winding layer of 30CF was about twice than that of 2CF-B. Therefore, stronger disturbance is induced in 30CF than in 2CF-B and this caused the difference of IC-XT."