Ultra-compact, ultra-low-loss and broadband 2 × 2 nonvolatile optical switch based on Sb₂Se₃ phase change material

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Nonvolatile optical switches are crucial for advanced photonic integrated circuits.
• Existing devices often face challenges with size, loss, and operational bandwidth.

Purpose of the Study:

• To propose and demonstrate an ultra-compact, broadband, nonvolatile 2x2 optical switch.
• To leverage the properties of phase change materials for efficient optical switching.

Main Methods:

• Fabrication of a device using two adjacent silicon waveguides embedded with antimony selenide (Sb2Se3).
• Characterization of the optical switch in both crystalline (Mach-Zehnder interferometer) and amorphous (directional coupler) states of Sb2Se3.
• Analysis of insertion loss, crosstalk, footprint, and operational bandwidth.

Main Results:

• The optical switch operates in bar state (crystalline) with 0.068 dB insertion loss and -31.97 dB crosstalk.
• The switch operates in cross state (amorphous) with 0.034 dB insertion loss and -29.27 dB crosstalk.
• Achieved ultra-low insertion loss (<0.17 dB) and crosstalk (< -15 dB) over a broadband of >64 nm with a compact footprint (∼3.6 × 27.6 µm²).

Conclusions:

• The proposed Sb2Se3-based nonvolatile optical switch demonstrates excellent performance metrics including compactness, ultra-low loss, and broadband operation.
• The device exhibits high tolerance to fabrication errors, indicating practical viability.
• This technology holds significant promise for future advanced photonic integrated circuits.