An efficient and compact mid-infrared polarization splitter and rotator based on a bifurcated tapered-bent waveguide

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Optics

Background:

• Mid-infrared (MIR) applications require specific light polarizations.
• Quantum cascade lasers emit transverse magnetic (TM) modes, incompatible with many on-chip devices.
• Existing MIR polarization control solutions are limited, especially on silicon-on-insulator (SOI) platforms.

Purpose of the Study:

• To present predictive simulations for a novel MIR polarization splitter and rotator (PSR).
• To enable transverse electric (TE) mode generation at both ports of a PSR on an SOI platform.
• To address the need for TE mode compatibility in MIR sensing and monitoring applications.

Main Methods:

• Utilized predictive simulations to design and analyze a novel MIR PSR.
• Focused on device operation within the 3.1-3.6 µm wavelength range.
• Investigated performance metrics including insertion loss, TM to TE power conversion loss, and crosstalk.

Main Results:

• The proposed MIR PSR operates on an SOI platform, a first for this wavelength range.
• Achieved TE insertion loss < 0.5 dB over a 500 nm range.
• Demonstrated TM to TE power conversion loss < 0.5 dB over a 400 nm range.
• Maintained crosstalk < 20 dB over a 400 nm wavelength range.

Conclusions:

• The novel MIR PSR design offers outstanding performance for on-chip polarization control.
• This SOI-based solution is vital for advancing MIR sensing, biological detection, and environmental monitoring.
• The device facilitates efficient conversion of TM modes from quantum cascade lasers to TE modes for broader device compatibility.