Watt-level all polarization-maintaining femtosecond fiber laser source at 1100 †nm.

We demonstrate a compact watt-level all polarization-maintaining (PM) femtosecond fiber laser source at 1100 nm. The fiber laser source is seeded by an all PM fiber mode-locked laser employing a nonlinear amplifying loop mirror. The seed laser can generate stable pulses at a fundamental repetition rate of 40.71 MHz with a signal-to-noise rate of >100 dB and an integrated relative intensity noise of only ∼0.061%. After two-stage external amplification and pulse compression, an output power of ∼1.47 W (corresponding to a pulse energy of ∼36.1 nJ) and a pulse duration of ∼251 fs are obtained. The 1100 nm femtosecond fiber laser is then employed as the excitation light source for multicolor multi-photon fluorescence microscopy of Chinese hamster ovary (CHO) cells stably expressing red fluorescent proteins.

Low-noise mode-locking in a GHz repetition rate Tm3+-doped fiber laser.

We demonstrate a GHz repetition rate mode-locked Tm3+-doped fiber laser with low noise. Based on a home-made Tm3+-doped barium gallo-germanate fiber with reduced dispersion, a broad optical spectrum of mode-locking is achieved, and its amplified spontaneous emission quantum-limited timing jitter is largely suppressed. Besides, we carefully investigate the influence of the intracavity pump strength on the noise performance of the mode-locked pulses and find that manipulating the intracavity pump power can be an effective method for optimizing the timing jitter and relative intensity noise (RIN). Particularly, RIN, which originated from the relaxation oscillation, can be effectively suppressed by 33 dB at offset frequencies of >1 MHz. The integrated timing jitter and RIN are only 7.9 fs (10 kHz-10 MHz) and 0.05% (10 Hz-10 MHz), respectively.

1200-W all polarization-maintaining fiber GHz-femtosecond-pulse laser with good beam quality.

In this work, we demonstrate a 1200-W average power all polarization-maintaining (PM) fiber ultrafast laser system operating at 1.0 µm. In accordance with the numerical modeling, the PM fiber laser system is designed and it delivers linearly-polarized femtosecond pulses at a 1.39-GHz fundamental repetition rate, with a maximum output power of 1214 W - to the best of our knowledge, the highest average power from all PM fiber ultrafast laser at 1.0 µm to date. The pulse width can be compressed to ∼800 fs with a beam quality of M2 < 1.1. This kilowatt-class all PM fiber laser system is expected to open new potential for high energy pulse generation through temporal coherent combination and laser ablation using GHz burst fs laser.

Manipulating the polarization dynamics in a >10-GHz Er3+/Yb3+ fiber Fabry-Pérot laser.

In this work, we report on the vector and scalar soliton dynamics that result from inevitable fiber birefringence in an 8-mm Er3+/Yb3+ fiber based Fabry-Férot (FP) laser that has a free spectral range of up to 12.5 GHz. The generation of polarization-evolving vector solitons can largely degrade the performance of application systems, and the underlying mechanisms and manipulation technologies are yet to be explored. To realize the transition from vector to scalar (linearly polarized) state, we here incorporate the polarization selection effect (PSE) in the simulation model and the numerical results verify that only a small amount of PSE is sufficient for manipulating the soliton dynamics. It also reveals that, prominent polarization-dependent intensity discrimination can be acquired via geometry-induced oblique incidence to the Bragg mirror of the semiconductor saturable absorber mirror (SESAM), and we obtain switchable operating states by tilting the SESAM in the experiments. These efforts create a feasible method to manipulate high-repetition-rate pulse and may shed light on understanding the dissipative soliton dynamics in ultrafast fiber FP lasers.