title: 88 W 0.5 mJ femtosecond laser pulses from two coherently combined fiber amplifiers.
abstract: The generation of 0.5 mJ femtosecond laser pulses by coherent combining of two high power high energy fiber chirped-pulse amplifiers is reported. The system is running at a repetition frequency of 175 kHz producing 88 W of average power after the compressor unit. Polarizing beam splitters have been used to realize an amplifying Mach-Zehnder interferometer, which has been stabilized with a Hänsch-Couillaud measurement system. The stabilized system possesses a measured residual rms phase difference fluctuation between the two branches as low as λ/70 rad at the maximum power level. The experiment proves that coherent addition of femtosecond fiber lasers can be efficiently and reliably performed at high B-integral and considerable thermal load in the individual amplifiers.
authors.affiliation: Institute of Applied Physics, Friedrich Schiller University Jena, Albert-Einstein-Strasse 15, 07745 Jena, Germany. enrico.seise@uni‐jena.de
authors.forename: Enrico
authors.initials: E
authors.lastname: Seise
authors.forename: Arno
authors.initials: A
authors.lastname: Klenke
authors.forename: Sven
authors.initials: S
authors.lastname: Breitkopf
authors.forename: Jens
authors.initials: J
authors.lastname: Limpert
authors.forename: Andreas
authors.initials: A
authors.lastname: Tünnermann