Ultra-compact, low-loss,TE₀- and TE₁-compatible mode waveguide bends.

Area of Science:

• Photonics and optical engineering
• Integrated optics
• Waveguide device design

Background:

• Waveguide bends are crucial for miniaturizing optical circuits by enabling light transmission in confined spaces.
• Achieving high curvature with low loss in waveguide bends is a significant challenge in integrated photonics.

Purpose of the Study:

• To propose and simulate novel waveguide bends capable of supporting two transverse electric (TE) modes (TE0 and TE1).
• To reduce the footprint and insertion loss (IL) of waveguide bends for compact and efficient optical devices.

Main Methods:

• Designing waveguide bends with etched slots and germanium arcs on the inner side.
• Utilizing simulations to analyze light field distribution and optimize structural parameters for TE0 and TE1 modes.
• Evaluating bending radius, insertion loss, footprint, and bandwidth performance.

Main Results:

• The proposed TE0 mode waveguide bend achieves a 500 nm bending radius with 0.13 dB IL and a 0.75 µm x 0.75 µm footprint.
• The TE1 mode waveguide bend demonstrates a reduced IL of 0.18 dB with a 1.85 µm x 1.85 µm footprint.
• Achieved bandwidths of 410 nm for TE0 and 330 nm for TE1 modes while maintaining IL < 0.5 dB.

Conclusions:

• The developed waveguide bends offer significant miniaturization and low loss for both fundamental and higher-order TE modes.
• The proposed design strategy shows potential for advanced applications in higher-order mode transmission and integrated photonic circuits.