Multiport Fiber Optic Beam Splitters for Space Division Multiplexed (SDM) Systems

We incorporate two major types of SDM fibers (i.e. few mode fibers and multicore fibers) in a micro-optic collimator assembly and realize fully integrated multiport SDM fiber components (e.g. <inline-formula> <tex-math notation="LaTeX">$1\times 2$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> beam splitters). The device fabrication procedure for SDM fibers is similar to that for a standard single mode fiber, but more accurate fiber alignment (e.g. lateral positioning for few mode fiber components and rotational alignment for multicore fiber components) is required to achieve both low mode (core) dependent loss and/or low inter-modal (inter-core) crosstalk. A number of exemplary multiport SDM components are fabricated with low excess loss (1-2.2 dB), low mode (core) dependent loss (< 1 dB) and moderate crosstalk (< −32 dB for a multicore fiber splitter and < −6.5 dB for a few mode fiber splitter).