High efficiency coherent beam combining of semiconductor optical amplifiers.

Area of Science:

• Optics and Photonics
• Laser Technology
• Semiconductor Devices

Background:

• High-power lasers are crucial for various applications.
• Coherent beam combining offers a path to increased output power.
• Optical waveguide amplifiers present a scalable platform for laser development.

Purpose of the Study:

• To demonstrate high-power, diffraction-limited beam output from a large array of optical amplifiers.
• To achieve efficient coherent combining of multiple laser emitters.
• To investigate the phase-locking stability and efficiency of the amplifier array.

Main Methods:

• Utilized a one-dimensional array of 47 angled-facet slab-coupled optical waveguide amplifiers.
• Employed a diffractive optical element and a common transform lens for beam collimation and overlap.
• Implemented active feedback control on individual amplifier drive currents for phase locking.

Main Results:

• Achieved 40 W of total output power in a single diffraction-limited beam.
• Demonstrated a consistent combining efficiency of 87% across various current levels.
• Successfully phase-locked all 47 amplifier elements.

Conclusions:

• Coherent beam combining of optical waveguide amplifiers is a viable method for achieving high-power laser output.
• The demonstrated technique offers high efficiency and scalability for future laser systems.
• The results pave the way for more powerful and compact laser sources.