Optical branching effect in Ti:LiNbO3 waveguides: near-field pattern studies

Area of Science:

• Optics and Photonics
• Materials Science
• Nonlinear Optics

Background:

• Photorefractive materials like Ti:LiNbO3 exhibit light-induced refractive index changes.
• Optical waveguides confine and guide light, enabling integrated photonic devices.
• Beam splitting (branching) is a fundamental phenomenon in optics with various applications.

Purpose of the Study:

• To investigate the beam branching effect in Ti:LiNbO3 optical slab waveguides.
• To analyze the influence of optical power and guided mode order on multibeam formation.
• To study the partial recovery of photorefractive damage in the waveguide.

Main Methods:

• Fabrication of Ti:LiNbO3 optical slab waveguides.
• Coupling of TE guided modes into the waveguide.
• Measurement and analysis of near-field patterns of the resulting multibeam structures.
• Observation of waveguide recovery after optical damage.

Main Results:

• Demonstration of a single optical beam splitting into multiple beams (branching effect).
• Near-field patterns revealed distinct multibeam structures dependent on optical power and mode order.
• Partial recovery of the optically damaged waveguide was observed, indicated by the shrinking of the multibeam bundle.

Conclusions:

• Ti:LiNbO3 waveguides exhibit significant beam branching due to photorefractive effects.
• Optical power and mode characteristics critically influence the branching dynamics.
• The photorefractive damage in these waveguides shows a degree of reversibility.