Silicon ring isolators with bonded nonreciprocal magneto-optic garnets.

Area of Science:

• Photonics and Materials Science
• Integrated Optics
• Magneto-optics

Background:

• Optical isolators are crucial components in photonic integrated circuits, preventing back reflections and ensuring signal integrity.
• Traditional optical isolators are often bulky and difficult to integrate onto chips.
• Developing compact, on-chip optical isolators is a key challenge in modern photonics.

Purpose of the Study:

• To demonstrate the first on-chip optical isolator using direct bonding of cerium-substituted yttrium iron garnet (Ce:YIG) onto a silicon ring resonator.
• To investigate the performance of such a device in terms of isolation and optical loss.
• To explore the potential of Ce:YIG and silicon photonics for integrated nonreciprocal devices.

Main Methods:

• Directly bonding a Ce:YIG layer onto a silicon ring resonator using oxygen plasma enhanced bonding.
• Fabricating a silicon waveguide with specific dimensions (600 nm width, 295 nm thickness) and a 500-nm-thick Ce:YIG layer.
• Applying a radial magnetic field to the fabricated ring isolator.

Main Results:

• Successful fabrication of a silicon ring isolator with integrated Ce:YIG.
• Achieved 9-dB isolation at resonance for the device.
• Demonstrated reasonable nonreciprocal effect and low optical loss at the 1550 nm wavelength.

Conclusions:

• The direct bonding of Ce:YIG onto silicon ring resonators is a viable method for creating on-chip optical isolators.
• The demonstrated device shows promising performance for integrated photonic applications.
• This work paves the way for miniaturized and efficient optical isolators in future photonic systems.