Integrated quasi-phase-matched second-harmonic generator and electro-optic phase modulator for low-noise...

Area of Science:

• Photonics
• Optical Engineering
• Nonlinear Optics

Background:

• Phase-sensitive amplifiers (PSAs) require high signal-to-noise ratio (SNR) pump light for optimal performance.
• Traditional methods for generating pump light often introduce noise, limiting PSA efficiency.
• Directly bonded lithium niobate (DB-LN) waveguides offer potential for integrated optical devices.

Purpose of the Study:

• To develop an integrated device for generating high-SNR pump light for PSAs.
• To enhance the performance of PSAs by suppressing noise from pump light sources.
• To demonstrate the effectiveness of a novel PSA configuration using a DB-LN waveguide.

Main Methods:

• Integration of a quasi-phase-matched second-harmonic generator with an electro-optic phase modulator in a DB-LN waveguide.
• Characterization of the device's modulation (1-MHz) and second-harmonic-generation (1-W) properties.
• Implementation of a novel PSA configuration leveraging the device's high-input-power tolerance.
• Comparison of noise figures between a PSA using the DB-LN waveguide and one using a Ti-diffused LN waveguide modulator.

Main Results:

• The integrated DB-LN waveguide device achieved 1-MHz modulation and 1-W second-harmonic generation.
• The novel PSA configuration successfully suppressed noise from the erbium-doped fiber amplifier.
• A significant improvement in the SNR of the pump light was observed.
• The DB-LN waveguide PSA demonstrated a lower noise figure compared to the Ti-diffused LN waveguide PSA.

Conclusions:

• The proposed integrated DB-LN waveguide device is effective for generating high-SNR pump light for PSAs.
• The novel PSA configuration enhances pump light quality and improves overall PSA performance.
• This technology offers a promising solution for noise reduction in optical amplification systems.