Normal dispersion femtosecond fiber optical parametric oscillator

High-energy normal-dispersion fiber optical parametric chirped-pulse oscillator

We demonstrate a fiber optical parametric chirped-pulse oscillator (FOPCPO) pumped in the normal-dispersion regime by chirped pulses at 1.036 µm. Highly chirped idler pulses tunable from 1210 nm to 1270 nm with energies higher than 250 nJ are generated from our system, along with signal pulses tunable from 870 nm to 910 nm. Numerical simulations demonstrate that further energy scaling is possible and paves the way for the use of such FOPCPOs for applications requiring high-energy, compact, and low-noise sources, such as in biophotonics or spectroscopy.

Noise-related polarization dynamics for femto and picosecond pulses in normal dispersion fibers

We report how the complex intra-pulse polarization dynamics of coherent optical wavebreaking and incoherent Raman amplification processes in all-normal dispersion (ANDi) fibers vary for femto and picosecond pump pulses. Using high temporal resolution vector supercontinuum simulations, we identify deterministic polarization dynamics caused by wavebreaking and self-phase modulation for femtosecond pulses and quasi-chaotic polarization evolution driven by Raman amplification of quantum noise for picosecond pulses. In contrast to cross-phase modulation instability, the Raman-based polarization noise has no power threshold and is reduced by aligning the higher energy polarization component with the lower index axis of the fiber. The degree of polarization stability is quantified using new time domain parameters that build on the spectrally averaged degree of coherence used in supercontinuum research to quantify the output spectral stability. We show that the spectral coherence is intrinsically linked to polarization noise, and that the noise will occur in both polarization maintaining (PM) and non-PM fibers, spanning a broad range of pulse energies, durations, and fiber birefringence values. This analysis provides an in-depth understanding of the nonlinear polarization dynamics associated with coherent and incoherent propagation in ANDi fibers.

Design guidelines for normal-dispersion fiber optical parametric chirped-pulse amplifiers

We theoretically investigate methods of controlling pulse generation in normal-dispersion fiber optical parametric chirped-pulse amplifiers. We focus on high-energy, ultrashort pulses at wavelengths widely separated from that of the pump, and find that within this regime, a number of simple properties describe the essential phase and gain dynamics. Of primary importance are the relationships between the chirps of the pump, seed, and parametric gain, which we theoretically predict and then experimentally validate. By properly arranging these parameters, the signal and idler waves can be widely customized to fulfill a remarkable range of application requirements, spanning from narrowband to few-cycle.

Watt-level all-fiber optical parametric chirped-pulse amplifier working at 1300 nm

We report watt-level average output power near 1300 nm from an all-fiber ultrafast optical parametric chirped-pulse amplifier. A compressed output pulse duration of ∼300  fs is achieved. Multiphoton imaging of a variety of samples carried out with this light source shows a good signal-to-noise ratio. With the demonstrated imaging capability, we believe that this high-power ultrafast laser source addresses a key need in deep tissue multiphoton microscopy.

Normal-dispersion fiber optical parametric chirped-pulse amplification

We demonstrate a fiber optical parametric chirped-pulse amplifier pumped in the normally dispersive regime. This approach is readily scalable, offering a route to microjoule-level, femtosecond pulses at new wavelengths. As a first demonstration, we pump with chirped pulses at 1.03 μm and seed with a continuous-wave beam at 0.85 μm, and are able to generate idlers at 1.3 μm with durations as short as 210 fs or energies as high as 180 nJ.

Optical parametric chirped pulse oscillation

A concept to flexibly adjust the spectral bandwidth of the output pulses of a fiber optical parametric oscillator is presented. By adjusting the chirp of the pump pulses appropriate to the chirp of the resonant pulses, the energy of the output pulses can be transferred into a user-defined spectral bandwidth. For this concept of optical parametric chirped pulse oscillation, we present numerical simulations of a parametric oscillator, which is able to convert pump pulses with a spectral bandwidth of 3.3 nm into output pulses with an adjustable spectral bandwidth between 9 and 0.05 nm. Combined with a wavelength tunability between 1200 and 1300 nm and pulse energies of up to 100 nJ, the concept should allow to adapt a single all-fiber parametric oscillator to a variety of applications, e.g., in multimodal nonlinear microscopy.

Optical parametric oscillator based on degenerate four-wave mixing in suspended core tellurite microstructured optical fiber

We report on a suspended core tellurite microstructured optical fiber (TMOF) based optical parametric oscillator (OPO). The intracavity gain is provided by the degenerate four-wave mixing (DFWM) occurred in a 1.5-m-long TMOF synchronously pumped by a mode-locked picosecond erbium-doped fiber laser. The oscillated signal can be generated from 1606 nm to 1743.5 nm, and the idler can be emited from 1526.8 nm to 1395 nm by adjusting the pump wavelength from 1565.4 nm to 1551 nm. A total intenal conversion efficiency of -17.2 dB has been achieved.

Four wave mixing of conventional and Raman dissipative solitons from single fiber laser

Conventional (1015 nm) and Raman (1055 nm) dissipative solitons generated in an all-fiber Yb laser are mixed in an external photonic crystal fiber (PCF) at pulse energy of up to 4 nJ at the input. It has been found that red-shifted ~20 ps pulses with energy up to 1 nJ are generated in the parametric process. Their peak wavelength is tunable from 1084 to 1102 nm by means of the delay variation between the input pulses. At that, the parametric pulses are shown to be coherent with the input ones and compressible to ~2 ps that is useful in applications. The performed modeling explains the main features of generated pulses.

High-power synchronously pumped femtosecond Raman fiber laser

We report a high-power synchronously pumped femtosecond Raman fiber laser operating in the normal dispersion regime. The Raman laser is pumped by a picosecond Yb(3+)-doped fiber laser. It produces highly chirped pulses with energy up to 18 nJ, average power of 0.76 W and 88% efficiency. The pulse duration is measured to be 147 fs after external compression. We observed two different regimes of operation of the laser: coherent and noise-like regime. Both regimes were experimentally characterized. Numerical simulations are in a good agreement with experimental results.