Integrated spatial light receivers based on inverse design.

Area of Science:

• Photonics
• Optical Communications
• Integrated Optics

Background:

• Photonic integrated spatial light receivers are vital for free space optical (FSO) communication.
• Efficiently receiving and processing multiple spatial modes is a key challenge in FSO systems.

Purpose of the Study:

• To propose and design novel 4-channel and 6-channel spatial light receivers using silicon-on-insulator (SOI) technology.
• To utilize inverse design methods for optimizing receiver performance.

Main Methods:

• Design of a 4-channel receiver with a square area (4.4 µm × 4.4 µm) for Hermite-Gaussian (HG) modes.
• Design of a 6-channel receiver with a hexagonal area for multiple HG modes.
• Analysis of performance metrics including insertion loss (IL), mean crosstalk (MCT), and 3dB bandwidth.
• Investigation of robustness against fabrication errors (etching, oxide thickness).

Main Results:

• The 4-channel receiver successfully receives four HG modes (HG00, HG01, HG10, HG02) with ILs of 1.6–2.1 dB and MCTs < -16 dB at 1550 nm.
• 3dB bandwidths for the 4-channel receiver range from 28–46 nm.
• The 6-channel receiver handles six HG modes (HG00, HG01, HG10, HG02, HG20, HG11) with ILs of 2.3–4.1 dB and MCTs < -15 dB.
• The 4-channel receiver demonstrates significant robustness against fabrication errors.
• The 6-channel receiver achieves a minimum optical bandwidth of 26 nm.

Conclusions:

• The proposed SOI-based spatial light receivers offer efficient multi-mode reception for FSO communications.
• The inverse design approach enables high-performance and robust photonic devices.
• These integrated receivers are promising for advancing FSO communication capabilities.