Ultra-Broadband Power Splitter With Arbitrary Splitting Ratio Based on SWG MMI Coupler

We propose and demonstrate an ultra-broadband power splitter with arbitrary splitting ratio based on subwavelength gratings (SWGs) multimode interference (MMI) coupler. SWGs are introduced to increase the optical bandwidth of the devices. Asymmetrical MMI regions are used to realize the arbitrary splitting ratio. We have demonstrated the realization of the low loss power splitters with the splitting ratio of 4:6 and 2:8. The measured results for the fabricated devices show that, for both 4:6 and 2:8 devices, loss less than 1.5 dB and splitting ratio variation less than 10% are achieved within a broad optical bandwidth from
$1.26~\mu $
m to
$1.6~\mu $
m.