3D integrated wavelength demultiplexer based on a square-core fiber and dual-layer arrayed waveguide gratings

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics

Background:

• Wavelength division multiplexing (WDM) is crucial for optical communication and sensing.
• Existing demultiplexers often face limitations in size, efficiency, or integration.

Purpose of the Study:

• To present a novel 3D integrated wavelength demultiplexer.
• To achieve efficient light splitting and wavelength demultiplexing using a square-core fiber and arrayed waveguide gratings.

Main Methods:

• Utilized a square-core fiber (SCF) as a 3D multimode interference device to split input light into four spots.
• Coupled the split light to a pitch-matched 4-waveguide network connecting dual-layer arrayed waveguide gratings (AWGs).
• Fabricated the device on a polymer platform using photolithography, optimizing interface waveguides for efficient coupling.

Main Results:

• Achieved a 3D integrated wavelength demultiplexer with a measured bandwidth of 112 nm across four AWGs.
• Demonstrated a small insertion loss variation of less than 1.4 dB among channels.
• The dual-layer fabrication allowed mapping of four different AWG designs to a single chip.

Conclusions:

• The developed 3D integrated wavelength demultiplexer offers efficient light splitting and demultiplexing.
• The device shows potential for applications in fiber optic sensing, communication systems, and astronomical instrumentation.
• The innovative use of SCF and dual-layer AWGs provides a compact and efficient solution for optical signal processing.