Asymmetric Y junctions in silicon waveguides for on-chip mode-division multiplexing

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Waveguide Devices

Background:

• Mode-division multiplexing (MDM) is crucial for increasing optical communication bandwidth.
• On-chip optical devices are essential for compact and efficient signal processing.

Purpose of the Study:

• To demonstrate silicon waveguide asymmetric Y junctions for mode multiplexers and demultiplexers.
• To analyze the performance of these devices for on-chip MDM applications.

Main Methods:

• Fabrication of silicon waveguide asymmetric Y junctions.
• Measurement of demultiplexed crosstalk and insertion loss across the C band.
• Analysis of device frequency response dependence on Y junction angle and interconnect length.

Main Results:

• Achieved demultiplexed crosstalk as low as -30 dB.
• Observed insertion loss below 1.5 dB for multimode links up to 1.2 mm.
• Demonstrated frequency response dependency on device geometry and advantageous interference effects.

Conclusions:

• Silicon waveguide asymmetric Y junctions are effective for low-crosstalk MDM.
• Compact Y junctions outside the mode-sorting regime can still yield high-performance MDM devices.