Co-planar arbitrary ratio optical power splitter based on cascaded hybrid-core vertical directional couplers for arbitrary guide modes

We propose a co-planar optical power splitter based on cascaded hybrid-core vertical directional couplers, which serves to split arbitrary ratio power of arbitrary guide modes. We fabricate the optical power splitter using micro-fabrication facilities. Our fabricated chip demonstrates power splitting for the E11, E21 and E12 modes between two few-mode waveguides. The experimental device shows that optical power splitting ranges can be larger than 11.0 dB, 12.1 dB and 11.3 dB for the E11, E21 and E12 modes, respectively, over the C + L band and beyond. The proposed optical power splitter could be used in the mode division-multiplexing systems where power splitting for arbitrary guide modes in few-mode waveguide is required in the ultra-broadband wavelength range for mode manipulating, such as mode power distribution, mode dependent loss equalization and all-optical MIMO signal processes.