March 3, 2026Open Access

High energy femtosecond mid-IR fiber CPA system at 2.79 µm using single mode operation of a coiled 46µm core Er:ZBLAN LMA fiber

Key Points

Powerful femtosecond pulses at 2.79 µm yield up to approximately 144 µJ of energy, a record for Er: ZBLAN lasers.
Measured pulse duration reached approximately 525 fs after compression, enhancing overall performance.
Assessment using a chirped-pulse amplification (CPA) system with large-mode-area fibers shows robustness in single-mode operation.
This advancement may enable new applications in medical and industrial settings, pushing the limits of fiber laser technology.

Abstract

We demonstrate the first large-core Er: ZBLAN fiber–based chirped-pulse amplification system operating at ∼2.79 µm. Single-mode amplification in a coiled 46 µm-core, ∼0.064 NA Er:ZBLAN fiber delivers up to ∼144 µJ of stretched femtosecond pulses (∼1.5 ns) at a 5.5 kHz repetition rate. After diffraction-grating compression, ∼70 µJ pulses with a duration of ∼525 fs are obtained. This represents what is believed to be a new record pulse energy for femtosecond-duration Er: ZBLAN fiber lasers, exceeding previous results by nearly two orders of magnitude. The performance is enabled by a diffraction-grating based CPA architecture combined with large-mode-area fiber operating robustly in a single transverse mode.

High energy femtosecond mid-IR fiber CPA system at 2.79 µm using single mode operation of a coiled 46µm core Er:ZBLAN LMA fiber

Key Points

Abstract

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