Low-loss and reflection-free fused type fan-out device for 7-core fiber based on a bundled structure

We describe a fused type fan-out device for 7-core fiber based on a bundled structure, which has no taper structure and a highly accurate core arrangement. We evaluated the repeatability of the splice loss characteristics of the fan-out device by splice testing 10 samples, resulting in an average splice loss of as low as 0.3 dB with a deviation of 0.048 dB. The crosstalk between the center and outer cores was less than −52 dB. Furthermore, the power damage threshold was higher than 1 W and the amount of Fresnel reflection at the splice point between the fiber bundle and the 7-core fiber was lower than the Rayleigh scattering level because of the arc fusion splicing.