Silicon reconfigurable mode-selective modulation for on-chip mode-multiplexed photonic systems

Recently, optical mode-division multiplexing has drawn a lot of attention due to its ability to increase the optical communication capacity in one physical channel with a single wavelength carrier. In this Letter, we demonstrate reconfigurable mode-selective modulation which is potentially useful for on-chip mode-multiplexed photonic systems. The device consists of two mode exchangers and one TE₁ mode modulator. The mode exchanger is based on a Mach-Zehnder interferometer that performs mode exchange between TE₀ and TE₁ modes. The TE₁ mode modulator consists of a pair of 1×3/3×1 multimode interferometers acting as a mode (de)multiplexer. It only selectively modulates the TE₁ mode while bypassing the TE₀ mode. 32 Gb/s on-off keying (OOK) modulation is successfully demonstrated for both input TE₀ and TE₁ modes. This device can be used as a building block for on-chip multimode interconnect networks.