Coherent combining of independently generated supercontinuum sources

Area of Science:

• Optics and Photonics
• Laser Physics
• Materials Science

Background:

• Coherent beam combining (CBC) is a technique for increasing laser brightness.
• Current CBC applications are limited to narrowband sources.
• Broadband supercontinuum sources require new scaling methods.

Purpose of the Study:

• To investigate the use of all-normal dispersion photonic crystal fibers (ANDi PCFs) for broadband coherent supercontinuum generation.
• To demonstrate a two-channel CBC architecture for scaling supercontinuum sources.
• To assess the feasibility of increasing brightness for broadband sources using CBC.

Main Methods:

• Experimental demonstration of a two-channel system using independent ANDi PCFs.
• Generation of supercontinuum spectra via ANDi PCFs.
• Recombination of spectra using a spectrally resolved Mach-Zehnder interferometer.
• Measurement of spectral coherence across the combined output.

Main Results:

• Achieved over 230 nm of spectral bandwidth.
• Produced approximately 300 mW of average power.
• Measured an average coherence of 0.71 across the spectrum.
• Successfully demonstrated a two-channel CBC system for supercontinuum generation.

Conclusions:

• All-normal dispersion photonic crystal fibers (ANDi PCFs) are suitable for broadband coherent supercontinuum generation.
• A two-channel CBC system can effectively scale the brightness of supercontinuum sources.
• This proof-of-concept experiment supports the development of multi-channel CBC architectures for further brightness scaling.