Mode multiplexer for guided optical and acoustic waves.

Area of Science:

• Photonics
• Acoustics
• Materials Science

Background:

• Integrated acousto-optic (AO) devices leverage strong acoustic and optical field overlap for efficient photon-phonon interactions.
• Acoustic waves provide a lossless modulation mechanism for light, crucial for photonic platforms.
• Current "Brillouin active" platforms aim to integrate optical, acoustic, and AO waveguide circuits on a single chip.

Purpose of the Study:

• To propose and describe a novel component for integrated photonic platforms: the acoustic-optical mode multiplexer (AOMM).
• To address the need for a device capable of multiplexing modes across optical and acoustic domains.
• To enable the development of new, efficient integrated AO devices by separating acoustic wave generation and opto-acoustic interaction.

Main Methods:

• Design and simulation of a suspended silicon-silicon dioxide structure for the AOMM.
• Characterization of mode coupling efficiency between optical and acoustic waveguides.
• Analysis of insertion loss and reflection parameters for optical and acoustic modes.

Main Results:

• Demonstration of an AOMM combining two optical modes and one acoustic mode into a single output waveguide.
• Achieved low insertion loss of 0.3 dB for both optical and acoustic modes.
• Reported reflection below -20 dB for optical modes and -11 dB for acoustic modes.

Conclusions:

• The proposed AOMM is a key enabling component for future integrated "Brillouin active" photonic platforms.
• This device facilitates efficient co-guidance of optical and acoustic modes, paving the way for advanced AO applications.
• The AOMM can lead to the creation of novel integrated AO devices like isolators and circulators.