Kim, Ilhwan Lee, Donghwa Hong, Seongjin Cho, Young-Wook Lee, Kwang Jo Kim, Yong-Su Lim, Hyang-Tag 2024-01-19T14:02:07Z 2024-01-19T14:02:07Z 2022-01-10 2021-08-30 1094-4087 https://pubs.kist.re.kr/handle/201004/116576 Linear optical multiports are widely used in photonic quantum information processing. Naturally, these devices are directionally-biased since photons always propagate from the input ports toward the output ports. Recently, the concept of directionally-unbiased linear optical multiports was proposed. These directionally-unbiased multiports allow photons to propagate along a reverse direction, which can greatly reduce the number of required linear optical elements for complicated linear optical quantum networks. Here, we report an experimental demonstration of a 3 x 3 directionally-unbiased linear optical fiber multiport using an optical tritter and mirrors. Compared to the previous demonstration using bulk optical elements which works only with light sources with a long coherence length, our experimental directionally-unbiased 3 x 3 optical multiport does not require a long coherence length since it provides negligible optical path length differences among all possible optical trajectories. It can be a useful building block for implementing large-scale quantum walks on complex graph networks. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement English OPTICAL SOC AMER COINCIDENCE COUNTING UNIT QUANTUM WALKS Implementation of a 3 x 3 directionally-unbiased linear optical multiport Article 10.1364/OE.436075 1 OPTICS EXPRESS, v.29, no.18, pp.29527 - 29540 OPTICS EXPRESS 29 18 29527 29540 scie scopus 000691863500124 2-s2.0-85114109672 Optics Optics Article COINCIDENCE COUNTING UNIT QUANTUM WALKS