Ultra-compact multimode waveguide bend based on a central width controllable dual Bezier structure

Area of Science:

• Photonics
• Optical Engineering
• Integrated Optics

Background:

• Multimode waveguide bends (MWBs) are critical components for mode-division multiplexing (MDM) systems.
• Achieving both compactness and high performance in MWBs remains a significant challenge, especially for higher-order modes.

Purpose of the Study:

• To present a novel optimization method for four-mode MWBs.
• To enable precise control over waveguide curvature and width for loss suppression.
• To achieve ultra-compact and high-performance MWBs.

Main Methods:

• Developed a four-mode MWB optimization technique.
• Utilized dual Bezier mathematical curves for bend design.
• Directly optimized the central width of the waveguide bend.

Main Results:

• Achieved a bending effective radius of 10 μm, the most compact design to date.
• Calculated minimal excess losses: 0.0114 dB (TE1), 0.0111 dB (TE2), 0.0047 dB (TE3), and 0.0310 dB (TE4) at 1550 nm.
• Demonstrated significant performance improvement for high-order modes in a compact footprint.

Conclusions:

• The proposed optimization method simplifies MWB design while enhancing performance.
• The ultra-compact MWB offers superior transmission efficiency, particularly for higher-order modes.
• This advancement is crucial for the development of practical and efficient MDM systems.