Kompetenzzentrum für optische Spezialfasern

e demonstrate a novel tuning concept for pulsed fiber-integrated lasers with a fiber Bragg grating (FBG) array as discrete and tailored spectral filter as well as a modified laser design. Based on a theta cavity layout, the structural delay lines originating from the FBG array are balanced enabling now a constant repetition rate and stable pulse properties over the full tuning range. The emission wavelength is electrically tuned with respect to the filter properties based on an adapted temporal gating scheme using an acousto-optic modulator. This concept has been investigated with an Yb-doped fiber laser demonstrating excellent emission properties with high signal contrast (>35 dB) and narrow linewidth (<150 pm) over a tuning range of 25 nm.