Coherent addition of high power laser diode array with a V-shape external Talbot cavity

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Laser Engineering

Background:

• Broad-area laser diode arrays are crucial for high-power applications.
• Achieving coherent beam combining in laser diode arrays is challenging due to spatial and spectral instabilities.
• External cavities are often employed to improve beam quality and spectral properties.

Purpose of the Study:

• To demonstrate high-power coherent laser beam combining from a broad-area laser diode array.
• To investigate the efficacy of a V-shape external Talbot cavity for mode discrimination and spectral narrowing.
• To validate numerical simulations of the far-field profile generated by a phase-locked array.

Main Methods:

• Design and implementation of a V-shape external Talbot cavity.
• Utilizing a broad-area laser diode array with a low filling-factor phase-locked configuration.
• Experimental demonstration of coherent beam combining and spectral linewidth measurement.
• Numerical simulation of the far-field beam profile.

Main Results:

• Successful coherent laser beam combining at high power was achieved.
• A narrow spectral linewidth was obtained.
• The V-shape external Talbot cavity demonstrated effective mode discrimination without a spatial filter.
• Numerical simulations confirmed a multi-lobe far-field profile for the phase-locked array.

Conclusions:

• The V-shape external Talbot cavity is an effective design for high-power coherent beam combining in broad-area laser diode arrays.
• This cavity design offers advantages in mode discrimination and simplifies the system by eliminating the need for a spatial filter.
• The study validates the performance of the V-shape cavity and provides insights into the beam characteristics of phase-locked arrays.