Extremely high extinction ratio electro-optic modulator via frequency upconversion to visible wavelengths.

Area of Science:

• Integrated photonics
• Nonlinear optics
• Quantum technologies

Background:

• Intensity modulators are crucial for integrated photonics, enabling applications in optical communication and quantum technologies.
• Existing electro-optic modulators offer high bandwidth and low-voltage operation but have moderate extinction ratios.
• Controlling atomic systems for quantum computing and clocks requires high-performance modulators.

Purpose of the Study:

• To present an integrated thin-film lithium niobate electro-optic modulator.
• To achieve a significantly enhanced extinction ratio for near-infrared light.
• To demonstrate the viability of second-harmonic generation for improving modulator performance.

Main Methods:

• Utilized a thin-film lithium niobate platform for electro-optic modulation.
• Incorporated a periodically poled waveguide for second-harmonic (SH) generation.
• Operated the modulator in the C-band, converting a 1536 nm signal to 768 nm.

Main Results:

• Demonstrated an upconverted signal retaining input signal characteristics.
• Achieved a high measured bandwidth of 35 GHz.
• Obtained a doubled extinction ratio of 46 dB, the highest recorded for NIR light on this platform.

Conclusions:

• The developed modulator offers superior extinction ratios for near-infrared light.
• Second-harmonic generation is an effective nonlinear process for enhancing modulator performance.
• This technology holds promise for advanced optical communication and quantum technology applications.