Consecutive 1015–1105-nm wavelength tunable “figure-of-9” mode-locked Yb:fiber oscillator

Abstract

A widely wavelength tunable mode-locked Yb-doped fiber oscillator based on nonlinear amplifier loop mirror (NALM) is reported, in which only a piece of short (∼0.5 m) single-mode polarization-maintaining (PM) Yb-doped fiber is employed, instead of the frequently used long (a few meters) double cladding (DC) fiber in previous papers. Experimentally, the center wavelength can be consecutively tuned from 1015 to 1105 nm by tilting the silver mirror, corresponding to a tuning range of 90 nm. To the best of our knowledge, this is the broadest consecutive tuning range in Yb:fiber mode-locked fiber oscillator. In addition, the mechanism of wavelength tuning is tentatively analyzed and attributed to the combined action of the spatial dispersion induced by a tilting silver mirror and the limited aperture in the system. Specific to the wavelength of 1045 nm, the output pulses with 13-nm spectral bandwidth can be compressed to 154 fs.

Coordination engineering in Nd3+-doped silica glass for improving repetition rate of 920-nm ultrashort-pulse fiber laser

“…Owing to their excellent performance in terms of short pulse duration and high peak power, ultrashort pulse lasers have gained much attention in the fields of fiber-optics communication, biophotonics, and industrial processing 1 – 8 Recently, because of the advantages of compactness, robustness, and freedom from maintenance over conventional solid-state lasers, 9 – 13 fiberized ultrashort pulses operating in the wavelength range from 900 to 950 nm produced by passive mode-locking techniques have become highly desirable for use in two-photon bioimaging (TPM) systems for the efficient excitation of green fluorescent proteins and their variants 14 – 18 Combined with nonlinear frequency conversion, 1.0-μm Yb3+-doped, 12 1.5-μm Er3+-doped, 19 and 1.9-μm Tm3+-doped 10 , 13 ultrashort fiber lasers have been utilized to achieve 900- ∼950-nm ultrashort pulses, which have propelled the advances of TPM systems, with the only drawback being the reduced all-fiber configuration as a result of using these additional nonlinear media.…”

Spectrally tunable phase-biased NALM mode-locked Yb:fiber laser with nJ-level pulse energy

“…self-start mode-lock. These fiber lasers have attracted significant attention in recent years thanks to their reliable, straightforward and robust operation [7][8][9][10][11].…”

“…For an overview of mode-locked fiber laser spectral tuning techniques, we refer the reader to Zhao et al [19]. The only method we are aware of that has been demonstrated to spectrally tune a phase-biased NALM laser is by rotating a mirror behind the intracavity grating pair [9,10]. In a configuration utilizing a double-clad Yb-doped gain fiber, with the phase bias applied in the NALM loop so that the grating pair and tilted mirror were directly behind a fiber collimator, it provided tuning over 1034-1104 nm [10].…”

“…In a configuration utilizing a double-clad Yb-doped gain fiber, with the phase bias applied in the NALM loop so that the grating pair and tilted mirror were directly behind a fiber collimator, it provided tuning over 1034-1104 nm [10]. When implemented in a laser with single-clad gain fiber, where the phase bias was applied in the free space section (same as shown in figure 1), the same method yielded tuning over 1015-1105 nm [9]. However, we observed that such tilting is accompanied by misalignment of the output beam, and in both cases operation was limited to low average output power (⩽15 mW) and pJ pulse energy.…”