Experimental investigation of relation between mode-coupling and fiber characteristics in few-mode fibers

We experimentally clarify that relation between mode-coupling coefficient h and effective-index difference Δn<sub>eff</sub> in few-mode fibers (FMFs) by impulse response technique and h in our fabricated FMFs with Δn<sub>eff</sub> ≥ 1.7 × 10<sup>-3</sup> converges to 7.4×10<sup>-5</sup> 1/km.