Integrated optical isolators using electrically driven acoustic waves.

Area of Science:

• Photonics
• Acousto-optics
• Integrated optics

Background:

• Photonic isolators are crucial for preventing back reflections in optical systems.
• Existing isolators often rely on bulky magneto-optic materials or complex designs.
• There is a need for compact, low-power, and easily integrated optical isolators.

Purpose of the Study:

• To propose and investigate an integrated photonic isolator based on non-reciprocal mode conversion.
• To demonstrate a device utilizing unidirectional acoustic waves for isolation.
• To evaluate the performance and integration potential of the proposed isolator.

Main Methods:

• Utilizing a triply-guided waveguide system with two optical modes and one acoustic mode.
• Implementing non-reciprocal mode conversion driven by traveling acoustic waves.
• Integrating spatial mode filters with the waveguide system to achieve isolation.

Main Results:

• Simulations predict over 20 dB isolation and 2.6 dB insertion loss.
• The device operates with a 370 GHz optical bandwidth and 1 cm length.
• Achieved isolation requires only 1 mW of electrical drive power, a significant reduction from state-of-the-art.

Conclusions:

• The proposed acoustic-wave-based photonic isolator offers high performance with low power consumption.
• The absence of magneto-optic materials and low drive power facilitate integration with CMOS platforms.
• This technology enables the development of compact, 'black box' optical isolators for advanced photonic systems.