GaInAsP/InP MZI waveguide optical isolator integrated with spot size converter

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Semiconductor Devices

Background:

• Waveguide optical isolators are essential components in optical communication systems to prevent back reflections.
• Integrating isolators directly onto semiconductor platforms offers potential for miniaturization and cost reduction.
• Existing isolator designs often face challenges with efficient fiber coupling and device footprint.

Purpose of the Study:

• To fabricate and characterize a novel waveguide optical isolator using a Gallium Indium Arsenide Phosphide (GaInAsP) guiding layer.
• To enhance fiber coupling efficiency through the integration of spot size converters (SSCs).
• To demonstrate the performance of the proposed isolator design based on a Mach-Zehnder interferometer (MZI) configuration.

Main Methods:

• Fabrication of a GaInAsP waveguide structure incorporating spot size converters (SSCs).
• Integration of a Mach-Zehnder interferometer (MZI) with multi-mode interference (MMI) couplers.
• Construction of a nonreciprocal phase shifter using a magneto-optical cladding layer bonded to the semiconductor guiding layer.

Main Results:

• The fabricated waveguide optical isolator achieved a maximum optical isolation of 28.3 dB.
• The device operated effectively at a wavelength of 1558 nm for the transverse magnetic (TM) mode.
• Successful integration of SSCs facilitated efficient coupling to optical fibers.

Conclusions:

• The developed GaInAsP waveguide optical isolator demonstrates high performance suitable for optical communication applications.
• The MZI-based design with a magneto-optical cladding offers an effective approach for nonreciprocal light propagation.
• The integration of SSCs addresses the critical challenge of efficient fiber-to-waveguide coupling in photonic integrated circuits.