Sub-1 Volt and high-bandwidth visible to near-infrared electro-optic modulators

Area of Science:

• Photonics and optical engineering
• Materials science
• Quantum information science

Background:

• Integrated electro-optic (EO) modulators are crucial for telecommunications and quantum processing.
• Existing thin-film lithium niobate modulators excel at telecommunication wavelengths but not in the visible-to-near-infrared (VNIR) spectrum.
• Applications in optical imaging, optogenetics, and quantum science necessitate VNIR EO devices.

Purpose of the Study:

• To develop and characterize high-performance VNIR amplitude and phase modulators.
• To demonstrate novel photonic applications using these VNIR EO modulators.

Main Methods:

• Fabrication of Mach-Zehnder modulators using thin-film lithium niobate.
• Characterization of voltage-length product (VπL), optical loss, and electro-optic (EO) bandwidth at VNIR wavelengths.
• Demonstration of integrated EO frequency combs and EO frequency shifting techniques.

Main Results:

• Achieved sub-1 V·cm VπL, as low as 0.55 V·cm at 738 nm.
• Reported low on-chip optical loss of ~0.7 dB/cm.
• Demonstrated EO bandwidths exceeding 35 GHz.
• Showcased integrated EO frequency combs with over 50 lines and tunable spacing.
• Implemented EO shearing for frequency shifting up to 7x the Fourier limit.

Conclusions:

• Successfully realized high-performance VNIR amplitude and phase modulators.
• These VNIR modulators enable advanced applications such as tunable EO frequency combs and enhanced frequency shifting.
• The developed devices significantly expand the utility of integrated photonics in the VNIR spectrum for diverse scientific fields.