Generation of synchronized femtosecond and picosecond pulses in a dual-wavelength femtosecond Ti:sapphire laser

Dynamics of dissipative soliton molecules in a dual-wavelength ultrafast fiber laser

Optical solitons, particle-like excitations ubiquitous in many fields, can bind to form soliton molecules with striking molecule-like interactions. However, the exotic soliton interactions in soliton molecules are still largely unexplored in dual-wavelength mode-locked fiber lasers. Here, we reveal the dynamics of dissipative soliton molecules with periodic solitons collision in a dual-wavelength ultrafast fiber laser. The soliton molecules with a central wavelength of 1532.8 nm and 1561 nm exhibit conspicuously different evolution characteristics attributed to the difference in gain spectral intensity and trapped potential. The long-wavelength soliton molecule swiftly recovers to the initial state after collision, while the short-wavelength soliton molecule has a remarkable variation in temporal separation and operation state. Moreover, the multiple intensive repulsion and attraction in soliton molecule with energy transfer between leading and trailing solitons, and the formation of triplet soliton molecule in short-wavelength with multiple switching have also been observed. The different oscillating solutions coexisting in dual-wavelength soliton molecules involving oscillating and sliding phase evolution confirm the multistability of the dissipative system. These findings shed new insights into the dynamics of soliton molecules and solitons collision in nonlinear systems.

Synchronization of nonsolitonic Kerr combs

Synchronization is a ubiquitous phenomenon in nature that manifests as the spectral or temporal locking of coupled nonlinear oscillators. In the field of photonics, synchronization has been implemented in various laser and oscillator systems, enabling applications including coherent beam combining and high-precision pump-probe measurements. Recent experiments have also shown time-domain synchronization of Kerr frequency combs via coupling of two separate oscillators operating in the dissipative soliton [i.e., anomalous group velocity dispersion (GVD)] regime. Here, we demonstrate all-optical synchronization of Kerr combs in the nonsolitonic, normal GVD regime in which phase-locked combs with high pump-to-comb conversion efficiencies and relatively flat spectral profiles are generated. Our results reveal the universality of Kerr comb synchronization and extend its scope beyond the soliton regime, opening a promising path toward coherently combined normal GVD Kerr combs with spectrally flat profiles and high comb-line powers in an efficient microresonator platform.

Passively synchronized dual-color mode-locked fiber lasers based on nonlinear amplifying loop mirrors

We have proposed and implemented a scheme for passive all-optical synchronization between erbium and ytterbium mode-locked fiber lasers. The passive locking of repetition rates for the dual-color pulses was realized by cross-phase modulation within phase-biased nonlinear amplifying loop mirrors. In contrast to previous demonstrations, the synchronization system was configured in an all-polarization-maintaining structure, thus gaining substantially improved stability and robustness. Consequently, the maximum tolerance of a cavity-length mismatch of 16.2 mm was achieved unprecedentedly, which was at least one order of magnitude longer than previously reported results for comparable temporal durations of involved pulses. The corresponding relative timing jitter was measured to be 31 fs within a 1 MHz bandwidth. Such a tight and robust synchronization fiber laser system offers great potential for various applications such as pump-probe microscopy, Raman scattering spectroscopy, and nonlinear frequency generation.

Dual-wavelength synchronously mode-locked Nd:LaGGG laser operating at 1.3 μm with a SESAM

A diode-end-pumped synchronously dual-wavelength mode-locked Nd:LaGGG laser operating at 1.3 μm with a semiconductor saturable absorber mirror was demonstrated for the first time.

Two synchronized modes of ultrashort optical pulses in a two-beam pumped Ti:sapphire laser

A two-beam-pumped dual-cavity Ti:sapphire laser in which femtosecond and picosecond laser pulses can be produced has been constructed. Two synchronized modes, femtosecond-femtosecond pulse synchronization and femtosecond-picosecond pulse synchronization, have been achieved. In the mode of femtosecond-femtosecond pulse synchronization, laser pulses of 26 and 23 fs were generated in the two laser cavities, with a timing jitter of 7 fs. In the mode of femtosecond-picosecond pulse synchronization, laser pulses of 29 fs and 1.49 ps were generated in the femtosecond and picosecond cavities, respectively, with a timing jitter of 30 fs. Several factors affecting the tunability and stability of the laser were analyzed. The results show that the operating stability and pulse synchronization are primarily governed by cross-phase modulation, which is closely related to the power ratio of the two pump beams in the two laser cavities.

Dual-wavelength passively mode-locked Nd:LuYSiO5 laser with SESAM

A diode-end-pumped dual-wavelength mode-locked laser based on Nd:LuYSiO5 crystal is demonstrated. With a SESAM, simultaneous mode locking at the 1075.8 nm and 1078.1 nm is achieved and the dual-wavelength mode locked pulses have a pulse width of 8.9 ps. Due to frequency beating, ultrahigh repetition rate ultrafast pulses with 997 fs pulse width and 0.59 THz repetition rate are further formed. Under 12.7 W absorbed pump power 1.7 W mode-locked output power was obtained, the slope efficiency of the mode locked laser was 24.3%.

Dual-wavelength mode-locked Yb:YAG ceramic laser in single cavity

We experimentally demonstrated a dual-wavelength independently mode-locked Yb:YAG ceramic laser in a single cavity. Dual-wavelength mode locking at 1033.6 and 1047.6 nm was operated simultaneously in one beam. Each pulse width was measured to be approximately 380 fs using an autocorrelator. The spectral widths were 4.50 nm centered at 1033.6 nm and 3.08 nm centered at 1047.6 nm. To the best of our knowledge, this is the first dual-wavelength mode locking achieved in Yb-doped solid-state lasers.

Square nanosecond mode-locked Er-fiber laser synchronized to a picosecond Yb-fiber laser

A mode-locked Er-doped fiber laser was triggered to synchronize with a separate ultrashort picosecond Yb-doped fiber laser by cross phase modulation. Square nanosecond pulses were generated in the long-cavity Er-fiber laser by the peak intensity clamp effect while the synchronization maintained. At the maximum pump power of 450 mW, a synchronous laser pulse duration of 5.5 ns has been achieved. This synchronous nanosecond and picosecond system has shown a large length mismatch tolerance of 2.6 mm and can work stably for days.

High-order dispersion-resulted tunable multiwavelength femtosecond laser

Resonant dispersive waves generated by high-order dispersion in a Ti:sapphire mode-locked solitary laser are investigated and experiments are found to be in good agreement with theoretical analysis. Both theory and experiment show that the wavelength differences can be tuned in a large range via changing the cavity dispersion. This simple technique can be applied to the fields where tunable femtosecond pulses at multiple wavelengths are needed. The described mechanism may be applied in other systems where solitons are known to exist.