Tunable Solc-type filter in periodically poled LiNbO(3) by UV-light illumination

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• Periodically poled lithium niobate (PPLN) is a key material for nonlinear optical applications.
• Solc-type filters offer wavelength selectivity but often require external tuning mechanisms.
• Photovoltaic effects in PPLN can induce internal electric fields.

Purpose of the Study:

• To demonstrate a tunable Solc-type filter in PPLN using UV-light illumination.
• To investigate the mechanism of filter formation via the photovoltaic effect.
• To quantify the wavelength tunability and its dependence on UV illumination.

Main Methods:

• Fabrication of a Solc-type filter within a PPLN waveguide.
• Illumination of the PPLN device with a uniform UV light source.
• Measurement of transmission spectra to observe wavelength shifts.
• Systematic variation of UV illumination intensity to study its effect.

Main Results:

• A tunable Solc-type filter was successfully demonstrated in PPLN.
• UV light illumination induced a significant wavelength shift (up to 15nm) via the photovoltaic effect.
• The wavelength shift exhibited a nearly linear relationship with UV illumination intensity.
• A tuning rate of approximately 52 mW/cm(2) per nm was achieved at 20°C.

Conclusions:

• UV-light-induced photovoltaic effect provides an effective method for tuning Solc-type filters in PPLN.
• This technique enables efficient, field-free wavelength filtering.
• The demonstrated tunability offers potential for advanced optical communication and sensing applications.