13 results about "Nonlinear phase shift" patented technology

The application relates to a full-polarization-maintaining fiber femtosecond laser based on a mode-locking starting promotion structure. The laser comprises a nonlinear amplification ring mirror with a double-path gain fiber, can realize continuous adjustment of a phase difference, introduces a nonlinear phase shift related to laser pulse intensity, reduces a mode-locking threshold of the nonlinear amplification ring mirror laser, improves self-starting mode-locking capability of the laser, and outputs high-power and high-stability ultrashort pulses; a non-reciprocal phase shift element introduces a linear phase shift bias for clockwise and counterclockwise propagation pulses; a linear arm introduces an optical element with a dispersion compensation function, ensures compactness of the oscillator, is used for outputting pulses, simultaneously provides seed pulse pre-chirp management for subsequent higher-power amplification, and realizes flat wide spectrum. The laser adopts a full-polarization-maintaining fiber structure, has good self-starting mode-locking characteristics, is beneficial to pulse filtering and shaping, and simultaneously has the advantages of compact structure, good stability, high damage threshold, high output power and low noise.

The present invention relates to a method for generating periodic pulses based on cascaded positive and negative nonlinear phase shift modulation. A negative phase shift plate utilizes a cascaded second-order nonlinear process to produce a redshift in the spectrum, while a positive second-order phase shift plate utilizes a femtosecond filament plasma to produce a blueshift in the spectrum. A first stage of positive and negative phase shift plates, both of which exhibit second-order nonlinear phase shifts, is constructed. Multiple stages are cascaded sequentially. By modulating each stage with equal phase shifts but opposite signs, the laser light passing through the multiple cascaded positive and negative phase shift plates broadens the spectrum to a supercontinuum exceeding 100 nm, with a linear chirp. This method achieves broadband coherent radiation, which is difficult to achieve with traditional methods, and can achieve a spectral bandwidth exceeding 100 nm, providing an effective approach for achieving periodic pulses of 1030 nm.

The invention belongs to the technical field of lasers, and particularly provides a high repetition frequency 9-shaped cavity fiber laser which comprises a wavelength division multiplexing coupler, a laser output assembly and a nonreciprocal phase shift assembly used for generating nonlinear phase shift. The non-reciprocal phase shift assembly comprises a phase shifter and a tapering optical fiber; the phase shifter is located on an emergent light path of the wavelength division multiplexing coupler; the input end of the tapering optical fiber is located on an emergent light path of the phase shifter, and the output end of the tapering optical fiber is connected with the wavelength division multiplexing coupler; the laser output assembly is connected with the wavelength division multiplexing coupler; and the laser output assembly is used for reflecting one part of the laser input by the wavelength division multiplexing coupler back to the wavelength division multiplexing coupler and outputting the other part of the laser. According to the high repetition frequency 9-shaped cavity fiber laser, the tapering fiber area is integrated in the non-reciprocal phase shift section, so that non-linear phase shift enough for mode locking can be generated without a very long passive fiber, the cavity length is shortened, the repetition frequency is improved, and the fiber laser can output laser with high repetition frequency.

The application discloses a GHz high-repetition 9-shaped cavity mode-locked fiber laser and a starting method thereof, and particularly relates to the technical field of ultrafast laser, a nonlinear amplification ring mirror, and an auxiliary starting light path arranged outside the nonlinear amplification ring mirror and used in a mode-locked starting stage; the auxiliary starting light path comprises a second reflector, a focusing lens and a semiconductor saturable absorber mirror. The GHz high-repetition 9-shaped cavity mode-locked fiber laser and the starting method thereof have the advantages that by introducing an external and separable auxiliary starting light path, seed light with high peak power is formed in the starting stage, the problem that a nonlinear phase shift difference of an extremely short cavity length is insufficient to cause mode-locked difficulty is effectively solved, stable mode locking of GHz-level repetition frequency pulse output is realized, in a steady-state operation stage, the laser completely relies on the nonlinear amplification ring mirror with low noise and high stability to realize mode locking, and high-stability, low-noise and repetition frequency ≥1GHz pulse output is obtained.

The invention provides a broadband Doherty power amplifier with an adaptive phase shift structure, and belongs to the technical field of power amplifiers. In order to cope with the phase mismatch problem, a self-adaptive phase shift structure is introduced and is arranged in front of an auxiliary driving amplifier unit, and nonlinear phase shift is superposed on an input signal of the auxiliary driving amplifier unit; meanwhile, the overall efficiency and linearity are prevented from being affected by insertion loss. In a broadband scene, the adaptive phase shift structure can reconstruct a phase curve in real time according to a power state of an input signal, dynamically adjust phase synthesis of a main path and an auxiliary path of the Doherty power amplifier, and ensure phase alignment and active regulation and control of load impedance in a frequency band, so that the overall efficiency of the Doherty power amplifier under the broadband is effectively improved. Moreover, the adaptive phase shift structure provides an on-chip adjustable scheme, so that the dependence on external elements is reduced, and the system complexity and the manufacturing cost are reduced.

The application relates to the technical field of lasers and discloses a self-starting 9-shaped cavity fiber laser with an adjustable feedback loop and a use method, which comprises a nonlinear amplification ring mirror and a linear arm, and a third coupler is arranged between the nonlinear amplification ring mirror and the linear arm; the nonlinear amplification ring mirror comprises a gain optical fiber, a polarization-maintaining wavelength division multiplexer and a phase shifter, the gain optical fiber, the polarization-maintaining wavelength division multiplexer and the phase shifter are sequentially and closely connected, and the polarization-maintaining wavelength division multiplexer is connected with a pump source; a feedback unit is arranged on the nonlinear amplification ring mirror, and the feedback unit is in communication with the gain optical fiber and the polarization-maintaining wavelength division multiplexer at two ends, respectively; and the light output from the rear end of the gain optical fiber is fed back to the gain optical fiber through the feedback unit to form a feedback loop. The application enhances the noise energy in the cavity by constructing a closed-loop feedback loop, reduces the mode-locking threshold and the starting time, dynamically adjusts the gain optical fiber amplification gain, stably controls the nonlinear phase shift accumulation, avoids an external complex system, and realizes the all-fiber low-to-high efficient design.

The invention belongs to the field of optical measurement, and particularly relates to a structured light nonlinear phase shift dynamic three-dimensional shape measurement method. Comprising the following steps: acquiring a nonlinear phase shift fringe sequence, bringing nonlinear phase errors caused by motion into phase shift data, and constructing a new unknown nonlinear phase shift dynamic measurement signal model; based on a new unknown non-linear phase shift dynamic measurement signal model, performing spatial domain segmentation on the non-linear phase shift stripe sequences to obtain a series of small-size local stripe sequences; processing each local stripe sequence by adopting a nonlinear phase shift algorithm to obtain local three-dimensional morphology phase information corresponding to each local stripe sequence; performing global phase reconstruction according to the local three-dimensional morphology phase information corresponding to each local stripe sequence to obtain an accurate dynamic three-dimensional morphology measurement result; according to the method, the phase shift error introduced in the dynamic measurement process of the structured light is corrected by using the nonlinear phase shift algorithm, so that the precision of the multi-frame phase shift method in the dynamic three-dimensional shape measurement of the structured light is greatly improved.

The invention discloses a high-power laser spectrum shaping device and method based on a multi-pass structure, and relates to the technical field of laser. The device comprises an input unit, an output unit and a multi-way cavity, the input unit comprises a mode coupling lens, a reflecting mirror and an input mirror; the multi-pass cavity comprises a first reflecting mirror, a polarization selection element, a birefringent crystal and a second reflecting mirror; the output unit comprises an output mirror and a reflecting mirror; the multi-way cavity is used for realizing space folding of a laser optical path; and the output mirror is used for controlling the propagation range number of the laser in the multi-way cavity. According to the invention, nonlinear phase shift is accumulated in the material to realize wide-range spectrum broadening, and meanwhile, the birefringent crystal is used for spectrum shaping, so that the precise shaping capability of spectrum broadening is obtained. In addition, according to the technical scheme, a multi-pass structure is adopted, high-power laser can repeatedly pass through the same element to achieve large-scale broadening and shaping of the spectrum, the space size of the device is compressed, the number of optical elements is reduced, and cost is reduced.

The embodiment of the present application provides a kind of adjustable all-optical shaper, adjustable all-optical shaper parameter determination method and device.The shaper includes: MZI shaping module, first directional coupler and second directional coupler;MZI shaping module includes: upper arm and lower arm;The output end of first directional coupler is connected with the input end of MZI shaping module respectively;Upper arm includes: nonlinear optical fiber and adjustable optical phase shifter, for the nonlinear phase shift of one of the two optical signals in nonlinear optical fiber, and the phase shift of one optical signal after nonlinear phase shift is carried out by adjustable optical phase shifter with preset phase shift value;Lower arm includes: linear optical fiber, for the linear phase shift of one of the two optical signals in linear optical fiber;The input end of second directional coupler is connected with the upper arm and the lower arm of MZI shaping module.

The application discloses a kind of hollow-core fiber kerr effect nonlinear coefficient measurement method, device, equipment and storage medium, it is related to optical communication technical field, the method comprises the following steps: receiving the high-order modulated signal of transmission in the launch end to be measured hollow-core fiber, high-order modulated signal is demodulated, and high-order demodulation signal is obtained;High-order demodulation signal is mapped to constellation diagram, and the nonlinear phase shift of high-order demodulation signal in constellation diagram is determined;Based on the nonlinear phase shift of high-order demodulation signal in constellation diagram and the pre-constructed kerr effect nonlinear mathematical model, the kerr effect nonlinear refractive index coefficient of to-be-measured hollow-core fiber is determined;Based on the kerr effect nonlinear refractive index coefficient of to-be-measured hollow-core fiber, the communication performance of to-be-measured hollow-core fiber is optimized.Through the above-mentioned mode, the mapping point in the signal constellation diagram after demodulation is analyzed, and the nonlinear phase shift is determined, so as to accurately calculate the kerr effect nonlinear refractive index coefficient by using nonlinear mathematical model and nonlinear phase shift.

A B integral and nonlinear refractive index measuring method based on a near-field regulation and control technology comprises the following steps: adjusting a loading pattern of an amplitude type liquid crystal spatial light modulator by using the amplitude type spatial light modulator according to the light intensity distribution of an incident laser beam and the spatial resolution of a wavefront sensor, and shaping the shape of the incident laser beam; light intensity distribution with gradient intensity is formed and is emitted to a to-be-detected sample; and receiving a light beam emitted from the to-be-measured sample by using a wavefront sensor, selecting a spatial light beam shape containing a high-intensity region in which B integral is accumulated and a low-intensity region in which B integral is not accumulated, extracting total nonlinear phase shift by using the low-intensity region as a reference point, and calculating to obtain B integral and nonlinear refractive index. The non-linear refractive index of a single material can be measured, B integral accumulated in a section of light path can also be measured, a sample cannot be damaged in the measurement process, and measurement is accurate.

The present invention discloses an ultrashort pulse generation device and method based on a concave spherical lens and a multi-pass cavity, which are used to obtain ultrashort pulse lasers with a pulse width of less than 40 femtoseconds and improve the stability of the pulse laser beam mode. The device of the present invention includes a femtosecond fiber laser, a pre-chirp control module, a beam mode matching module, a nonlinear spectrum broadening module, and a dispersion compensation module. The nonlinear spectrum broadening module broadens the laser pulse spectrum by passing the light beam through a pair of self-phase modulation media multiple times in the multi-pass cavity. The self-phase modulation medium reduces the nonlinear mode matching requirements. The method of the present invention is provided with a pre-chirp control module, and the self-phase modulation medium is used to adjust the nonlinear phase shift in the multi-pass cavity and reduce the self-focusing effect of the pulsed laser beam. The present invention has high generation efficiency and is applicable to input pulses with peak powers within a set range.

The application belongs to the technical field of lasers, and specifically provides a high-repetition-frequency 9-shaped cavity fiber laser, which comprises a wavelength division multiplexing coupler, a laser output assembly and a non-reciprocal phase shift component for generating a nonlinear phase shift; the non-reciprocal phase shift component comprises a phase shifter and a polarization maintaining fiber; the phase shifter is located on an outgoing light path of the wavelength division multiplexing coupler; an input end of the polarization maintaining fiber is located on an outgoing light path of the phase shifter, and an output end of the polarization maintaining fiber is connected with the wavelength division multiplexing coupler; the laser output assembly is connected with the wavelength division multiplexing coupler; the laser output assembly is used for reflecting part of input laser of the wavelength division multiplexing coupler back to the wavelength division multiplexing coupler and outputting the other part. The high-repetition-frequency 9-shaped cavity fiber laser can generate sufficient nonlinear phase shift for mode locking without a long passive optical fiber by integrating the polarization maintaining fiber region in the non-reciprocal phase shift section, and then the cavity length is shortened and the repetition frequency is improved, so that the fiber laser can output laser with high repetition frequency.