The growth of bandwidth in optical metro and core transmission networks requires not only higher capacity but also densification of transmission lines and in-line components. Component sharing of these optical sub-systems is a simple and efficient way to achieve higher density.


The erbium doped fiber amplifiers (EDFAs) are critical and costly components; their footprint and cost reduction is already addressed by arrayed EDFAs merging mechanical enclosures, electronics and using multiple-chips pumps. Space Division Multiplexing allows to go further in the size and cost reduction, but also in power consumption reduction as it allows to share the same erbium doped fiber and pump source for amplifying several independent channels simultaneously.


CAILabs’ KIAMA 10-to-1 mode selective signal and pump multiplexer allows to build the next generation of arrayed EDFAs. It selectively input and output up to 10 spatial signal channels in the C-band into any multi-mode active fiber, and it additionally supports the spatial multiplexing of 2 modes at the pump wavelength. By using an adapted fiber, designed to lift mode group degeneracy, the guided modes do not mix in the active fiber and each signal mode is then used as a single transmission channel. Tailored pump modes allow to balance channels differential gain and improve the amplifier efficiency.