Stable low-loss proton-exchanged LiNbO(3) waveguide devices with no electro-optic degradation

Area of Science:

• Photonics and Waveguide Technology
• Materials Science
• Electro-Optics

Background:

• Lithium Niobate (LiNbO3) is a key material for integrated optics due to its excellent electro-optic properties.
• Fabrication of low-loss optical waveguides is crucial for developing advanced photonic devices.
• Annealed proton exchange (APE) is a common technique for fabricating waveguides in LiNbO3.

Purpose of the Study:

• To fabricate and characterize channel waveguides and Mach-Zehnder interferometers in LiNbO3 using the annealed proton exchange method.
• To evaluate the optical loss and electro-optic performance of the fabricated devices.
• To assess the long-term stability of these photonic components.

Main Methods:

• Fabrication of optical waveguides and Mach-Zehnder interferometers in LiNbO3 substrates via annealed proton exchange.
• Measurement of waveguide propagation loss at 0.8 microm wavelength.
• Characterization of the fiber-to-fiber insertion loss and the r(33) electro-optic coefficient of the interferometers.
• Long-term stability testing of device performance over an 8-month period at room temperature.

Main Results:

• Achieved low waveguide propagation loss of 0.15 dB/cm.
• Obtained a fiber-to-fiber insertion loss of 1.2 dB at 0.8 microm.
• Measured an r(33) electro-optic coefficient of 30 x 10(-12) m/V, consistent with theoretical values.
• Demonstrated no significant variation in insertion loss or switching voltage over 8 months of storage.

Conclusions:

• The annealed proton exchange method is effective for fabricating high-performance LiNbO3 channel waveguides and Mach-Zehnder interferometers.
• The fabricated devices exhibit excellent optical and electro-optic properties with no degradation over time.
• These results indicate the suitability of APE-fabricated LiNbO3 devices for stable, long-term photonic applications.