Compact 2 × 2 polarization-diversity Si-wire switch.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Silicon Photonics

Background:

• Polarization-dependent loss and performance variations are significant challenges in integrated optical devices.
• Silicon-wire waveguides offer potential for miniaturization but require careful design for polarization independence.

Purpose of the Study:

• To demonstrate a polarization-independent 2x2 optical switch using silicon-wire waveguides.
• To achieve compact device footprint and high performance metrics.

Main Methods:

• Implementation of a polarization-diversity technique incorporating polarization splitters and TE-TM mode intersections.
• Fabrication of Mach-Zehnder interferometer-based switches on silicon-wire platforms.
• Characterization of extinction ratios, switching powers, polarization-dependent loss, and differential group delay (DGD).

Main Results:

• Achieved a compact 2x2 switch (600 x 500 μm²) with polarization-independent operation.
• Measured extinction ratios >30 dB (TE, mixed) and >25 dB (TM) at 1550 nm.
• Reported switching powers of 25 mW (TE) and 55 mW (TM), with polarization-dependent loss <1 dB.
• Fabricated a path-length-compensated switch with DGD as low as ~2 ps.

Conclusions:

• The developed silicon-wire waveguide switch effectively overcomes polarization dependency.
• This technology provides a viable pathway for creating ultra-compact, polarization-independent integrated photonic circuits.