31 results about "Third order dispersion" patented technology

By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.

An optical component of the present invention is compensated its optical dispersion, including third order dispersion, at low loss using optical dispersion compensating element comprising multi-layer film. In the optical component, an optical dispersion compensating element and a functional element are connected in series along an optical path.

Embodiments of the present invention generally relate to high energy, ultrashort pulses from a net normal dispersion ytterbium fiber laser with an anomalous dispersion higher-order mode fiber. More specifically, embodiments of the present invention relate to a fiber oscillator with all-fiber dispersion compensation delivering pulse parameters comparable to solid-state oscillators having good compensation of higher order dispersion and intracavity nonlinearities. In one embodiment of the present invention, an oscillator comprises a length of single mode fiber and a length of higher-order mode fiber, where the group delay dispersion (GDD) of the higher-order mode fiber is chosen to match 50% or more of the GDD of the single mode fiber; wherein a third-order dispersion of the oscillator matches a nonlinear phase buildup in a cavity of the oscillator, and the nonlinear phase buildup is dependent upon the pulse energy of the oscillator.

An optical delay element including a photonic crystal line defect optical waveguide is disclosed that has a large group refractive index and has small or nearly constant wavelength dispersion of the group refractive index in a wide wavelength region for practical use. The optical delay element includes a line defect optical waveguide formed in a photonic crystal structure, and the volume of the line defect optical waveguide is less than the volume of a single line defect optical waveguide. Thereby, the waveguide band of the line defect optical waveguide has two zero points in the third order dispersion curve of the line defect optical waveguide, and the sign of the third order dispersion curve is inverted near the zero points. Therefore, the waveguide band of the line defect optical waveguide is modified, and this enables expansion of the wavelength region having a large group refractive index, small wavelength dispersion of the group refractive index, and small wavelength dispersion of the speed of optical pulses.

The invention discloses a dispersion compensation method based on a Fourier domain optical coherence tomography technology, which belongs to the technical field of optical coherence tomography. An interference signal is obtained according to a light intensity signal of output light of a Fourier domain optical coherence tomography system, then the interference signal is converted to obtain a complex interference signal, namely an analytic signal, a relation between a phase and a wave number is extracted, and third-order polynomial fitting is carried out; and finally, phase compensation is conducted on the analytic signal by utilizing the calculated second-order dispersion factor and third-order dispersion factor to realize the effect of eliminating the influence of high-order dispersion inthe Fourier domain optical coherence tomography imaging system and achieve the purpose of improving the axial resolution of the Fourier domain optical coherence tomography imaging system. The method is simple in operation mode, and dispersion compensation in continuous real-time imaging can be realized only by one-time measurement and calibration in an experiment.

The present invention relates to an OPCPA apparatus. The OPCPA of the present invention includes an optical pulse stretcher (100) for outputting chirped laser light using odd-order dispersion (third-order dispersion is mainly used). A pump laser (200) outputs pump laser light. An OPA unit (300) receives the pump laser light and the chirped laser light (signal), amplifies the signal using the pump laser light, and generates an idler. An optical signal separation unit (400) separates output light of the OPA unit into the signal, the idler, and remaining light (pump). An optical pulse compressor (600) compensates for pulse chirping caused by odd-order dispersion that is imparted by the optical pulse stretcher, thus temporally compressing the signal and the idler, which overlap each other.

The invention discloses a novel femtosecond optical fiber amplifier which is characterized by comprising the components of a femtosecond oscillation output module which is used for outputting polarized light with positive dispersion ray, a pre-compression module which is used for pre-compression and obtaining certain negative dispersion light, a double-clad optical fiber amplifying module which is used for energy amplification and restraining third-order dispersion through phase adjustment, and a secondary compression module which is used for outputting after secondary compression; wherein the femtosecond oscillation output module, the pre-compression module, the double-clad optical fiber amplifying module and the secondary compression module are successively arranged. The novel femtosecond optical fiber amplifier has a compact structure. Two compression modules are used and can perform cooperated adjustment for obtaining an optimal output pulse shape. Firstly, little negative dispersion is introduced into the femtosecond oscillation output module beforehand. Pre-amplification is performed through the pre-compression module. The pulse energy can be effectively amplified, and simultaneously a sidelobe energy caused by the third-order dispersion of an optical pulse after amplification is reduced, thereby obtaining the pulse with an approximate Fourier transform limited shape. The novel femtosecond optical fiber amplifier is particularly suitable for a micro-machining industry which is very sensitive to thermal effect.

A short pulse fiber laser amplification system includes a special fiber stretcher, managed preamplifier, managed amplifier chain, and managed compressor to control an increase of a passive dispersion by managing a third order dispersion (TOD) to a group velocity dispersion (GVD) ratio for matching a nonlinearity chirp. In an exemplary embodiment, the TOD to GVD ratio is managed between approximately 1.5 to 15 fs to match a nonlinearity in range between 1π to 10π. In another exemplary embodiment, the TOD to GVD ratio is managed between approximately 15 to 705 fs to match a nonlinearity in range between 1π to 50π.

The invention discloses a system and method for accurately measuring three-order dispersion of an optical fiber. The system comprises a wide spectrum light source, a light splitting device, an electro-optic modulator, a programmable optical processor, a light merging device, a photoelectric detector, a vector network analyzer and a processor. A passband broadening factor B is calculated by the processor according to system response data of the vector network analyzer, whether the passband broadening factor B exceeds a preset threshold is judged, and if so, the processor iteratively calculatesa dispersion compensation coefficient and continuously controls the programmable optical processor to produce a new compensation baseband signal until the passband broadening factor B does not exceedthe preset threshold. When the calculated passband broadening factor B does not exceed the preset threshold, it indicates that the three-order dispersion value in the optical fiber is accurately compensated, and the three-order dispersion value in the to-be-measured optical fiber is accurately determined according to the final passband broadening factor B in accordance with the relationship between the compensation amount and the residual amount.