Amorphous-Si waveguide on a garnet magneto-optical isolator with a TE mode nonreciprocal phase shift

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Optics

Background:

• Magneto-optical (MO) isolators are crucial components in optical systems, preventing back reflections.
• Existing MO isolators often face challenges in achieving efficient operation for specific light polarizations like the transverse electric (TE) mode.
• The development of compact and high-performance isolators is essential for advancing integrated photonic circuits.

Purpose of the Study:

• To design and fabricate a novel magneto-optical (MO) isolator.
• To achieve nonreciprocal phase shift specifically for the TE mode of light.
• To demonstrate efficient isolator operation in a fabricated device.

Main Methods:

• Fabrication of a Mach-Zehnder interferometer-based MO isolator.
• Design of a novel waveguide structure using hydrogenated amorphous silicon with asymmetric MO garnet cladding on a garnet substrate.
• Characterization of the device to measure forward and backward transmittances and isolation.

Main Results:

• Successful demonstration of isolator operation with distinct forward and backward transmittances.
• Achieved a maximum isolation of 17.9 dB at a wavelength of 1561 nm.
• Validated the TE mode nonreciprocal phase shift capability of the designed waveguide structure.

Conclusions:

• The novel waveguide structure enables efficient TE mode operation in MO isolators.
• The fabricated device confirms the effectiveness of the Mach-Zehnder interferometer design for nonreciprocal light propagation.
• This work presents a promising approach for developing advanced optical isolators for integrated photonics.