Design and fabrication of elliptical-core few-mode fiber for MIMO-less data transmission

Abstract

We propose a design strategy of elliptical core few-mode fiber (e-FMF) that supports three spatial modes with enhanced mode spacing between LP_11a and LP_11b, to suppress intra-mode coupling during mode-division multiplexing (MDM) transmission. Our theoretical investigations show that there exist two optimization regimes for the e-FMF, as a comparison with traditional circular core FMF(c-FMF). At the regime of three-mode operation, there occurs a trade-off between mode spacing and bending-induced loss. Meanwhile, in terms of five-mode regime, a trade-off between mode spacing and high-order mode crosstalk happens. Finally, we fabricate 7.94 km e-FMF with the optimal parameters, based on the commercial fiber manufacture facility. The primary characterizations at 1550 nm show that three spatial modes of e-FMF can be transmitted with a loss less than 0.3 dB/km. Meanwhile, -22.44 dB crosstalk between LP_11a and LP_11b is observed, even when the 2 km e-FMF is under stress-induced strong perturbation.

Fiber transmission demonstrations in vector mode space division multiplexing

“…Elliptical core waveguides are widely used to split the degeneracy of polarization states, reduce mode coupling and offer polarization maintaining properties to the optical fiber. However, few demonstrations of few mode polarization maintaining fibers have been achieved due to the difficulty to reach sufficient effective index separation while keeping higher order modes above cut-off [11]. In this work, we present two optical fibers with ring cores for transmission over vector modes, as represented in Fig.…”

Design and Characterization of Nanopore- Assisted Weakly-Coupled Few-Mode Fiber for Simpler MIMO Space Division Multiplexing

“…The fact is that the excessive changes in the core structure will alter fiber properties, such as transmission loss and increase the fabricating difficulty. Some elliptical cores are also designed to separate degenerate modes [9], [19], [20]. However, breaking the degeneracy usually brings an even smaller n eff , which will restrict the number of independent modes.…”

Design of Highly Elliptical Core Ten-Mode Fiber for Space Division Multiplexing With 2 × 2 MIMO

“…It would therefore be advantageous to design weakly-coupled FMF that exhibits only twofold polarization degeneracy because the needed DSP would become essentially the same as that of standard coherent receivers with polarizationdiversity. Recently, the use of elliptical core FMF to break the degeneracy between even and odd modes of non-rotational symmetric modes has been demonstrated [14]- [16]. For example, negligible modal crosstalk among three spatial modes (LP 01 , LP 11a and LP 11b ) was achieved even under bending [14].…”