Electro-optic Ti:PPLN waveguide as efficient optical wavelength filter and polarization mode converter

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Optics

Background:

• Periodically poled lithium niobate (PPLN) is a key material for nonlinear optical devices.
• Ti-indiffusion is a standard technique for fabricating optical waveguides in lithium niobate.
• Solc-type filters offer tunable spectral characteristics.

Purpose of the Study:

• To experimentally demonstrate electrically controlled Solc-type optical wavelength filters.
• To achieve efficient TE-TM mode conversion using Ti:PPLN waveguides.
• To investigate the performance and tunability of these integrated photonic devices.

Main Methods:

• Fabrication of multiple-grating Ti:PPLN waveguides.
• Experimental setup for measuring optical filter transmittance and mode conversion efficiency.
• Application of electrical voltage for device control and tuning.

Main Results:

• Achieved ~99% peak spectral transmittance and mode conversion efficiency in the telecom C-L bands.
• Demonstrated electrically controlled operation with a low switching voltage of 22 V (0.99 V·μm/cm).
• Showcased temperature tunability of the spectral range at ~0.758 nm/°C.

Conclusions:

• The study presents the first experimental realization of electrically controlled Solc-type filters and TE-TM mode converters in Ti:PPLN.
• The devices exhibit high performance, low voltage operation, and temperature tunability.
• This work offers a promising platform for reconfigurable optical signal processing and integrated photonic circuits.