Multimode interface between optical free-space and waveguide modes

Area of Science:

• Photonics and Optical Communications
• Integrated Optics
• Waveguide Technology

Background:

• Free-space and on-chip photonic systems are crucial for optical communication.
• Bridging free-space mode manipulation and integrated waveguide stability is vital for scalable networks.
• Higher-order spatial modes offer potential for increased data transmission capacity.

Purpose of the Study:

• To develop an efficient, broadband interface for converting free-space Laguerre-Gauss (LG) modes to waveguide modes.
• To demonstrate low-crosstalk mode conversion for multi-mode optical communication.
• To enable compact and efficient on-chip processing schemes for optical networks.

Main Methods:

• Utilized the multi-plane light conversion (MPLC) scheme for mode conversion.
• Experimentally demonstrated conversion between sets of three LG modes and the first three TE modes.
• Operated the system passively across the telecom C-band within a multimode silicon waveguide.

Main Results:

• Achieved efficient and broadband conversion of multiple higher-order free-space LG modes to waveguide modes.
• Demonstrated low-crosstalk mode conversion between specific LG and TE mode sets.
• Validated passive operation without active switching, adaptable to different spatial mode sets.

Conclusions:

• The developed interface efficiently bridges free-space and on-chip photonic systems.
• This technology offers a pathway to significantly increased data capacities in optical communication.
• The platform enables more compact and efficient multi-mode optical communication and on-chip processing.