Achromatic CMOS-Integrated Four-Bit Orbital Angular Momentum Mode Detector at Three Wavelengths

Area of Science:

• Optics and Photonics
• Integrated Photonics
• Information Processing

Background:

• Simultaneous detection of orbital angular momentum (OAM) and wavelength is crucial for advanced optical multiplexing.
• Dispersion in lens functions limits simultaneous mode conversion at distinct wavelengths in a single plane.

Purpose of the Study:

• To propose and demonstrate an ultracompact, achromatic OAM mode detector integrated with CMOS technology.
• To overcome the limitations of wavelength-dependent dispersion in OAM detection.

Main Methods:

• Development of a spatial multiplexing scheme with interleaved phase distributions.
• Fabrication of a nanoprinted achromatic OAM detector with microscale dimensions and short focal length.
• Integration of the detector onto a CMOS chip.

Main Results:

• Successful distinction of four-bit incident light beams at three discrete wavelengths (633, 532, and 488 nm).
• High accuracy in OAM mode detection, with an average standardized Euclidean distance of ~0.75.
• Demonstration of a miniaturized platform for high-capacity information processing.

Conclusions:

• The proposed achromatic OAM detector offers a compact and efficient solution for optical multiplexing.
• CMOS integration enables practical applications in high-capacity information processing.
• The technology paves the way for next-generation optical communication systems.