Distributed feedback-distributed Bragg reflector coupled cavity laser with a Ti:(Fe:)Er:LiNbO3 waveguide

Area of Science:

• Photonics and Laser Technology
• Materials Science (Lithium Niobate)
• Optical Engineering

Background:

• Photorefractive Bragg gratings are crucial for laser cavity design.
• Erbium-doped lithium niobate waveguides offer potential for integrated photonics.
• Distributed feedback (DFB) lasers require precise grating structures for single-frequency operation.

Purpose of the Study:

• To fabricate and characterize a thermally fixed photorefractive Bragg grating in a Ti:Fe:Er:LiNbO3 channel waveguide.
• To develop a distributed feedback-distributed Bragg reflector (DFB-DBR) coupled cavity laser.
• To investigate the laser's performance, including output power, efficiency, and tunability.

Main Methods:

• Writing a thermally fixed photorefractive Bragg grating in a single-mode Ti:Fe:Er:LiNbO3 channel waveguide.
• Coupling the waveguide grating with a broadband dielectric cavity mirror.
• Optically pumping the laser at 1480 nm with 130 mW power.
• Measuring laser output at 1557.2 nm.

Main Results:

• The DFB-DBR coupled cavity laser achieved single-frequency operation.
• Maximum output power of 8 mW was obtained.
• A slope efficiency of approximately 22% was demonstrated.
• The laser wavelength was tunable over 100 pm using thermo-optic and electro-optic effects.

Conclusions:

• A functional single-frequency laser was successfully developed using a novel waveguide Bragg grating.
• The demonstrated performance metrics highlight the potential of this integrated photonic approach.
• The tunable nature of the laser opens possibilities for various applications in optical communications and sensing.