Compact polarization-independent non-volatile optical switches.

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Semiconductor Devices

Background:

• Silicon photonics is vital for reconfigurable optical circuits.
• Silicon waveguides exhibit strong anisotropy, causing polarization-dependent performance in optical switches.
• Existing non-volatile optical switches often struggle with polarization independence.

Purpose of the Study:

• To propose and demonstrate a polarization-independent, non-volatile optical switch on a silicon platform.
• To utilize the low-loss phase change material (PCM) antimony trisulfide (Sb2S3) for enhanced optical switching.
• To achieve efficient and polarization-insensitive control of multimode interference (MMI).

Main Methods:

• Incorporation of Sb2S3 PCM into a multimode slot waveguide design.
• Optimization of the multimode slot waveguide region for polarization-independent operation.
• Characterization of the optical switch performance, including crosstalk (CT) and insertion loss (IL) at 1550 nm.

Main Results:

• Demonstration of a polarization-independent optical switch with crosstalk (CT) < -21.9 dB.
• Achieved insertion loss (IL) < 0.12 dB at 1550 nm.
• Efficient tuning of multimode interference for both TE and TM polarizations due to enhanced light-PCM interaction.

Conclusions:

• The proposed Sb2S3-based non-volatile optical switch effectively overcomes the polarization dependence of silicon waveguides.
• The device exhibits excellent performance metrics (low CT, low IL), making it suitable for advanced photonic applications.
• This technology holds promise for developing sophisticated reconfigurable photonic circuits and on-chip optical signal processing systems.