164 results about "Soliton" patented technology

An apparatus generates femtosecond pulses from laser amplifiers by nonlinear frequency conversion. The implementation of nonlinear frequency-conversion allows the design of highly nonlinear amplifiers at a signal wavelength (SW), while still preserving a high-quality pulse at an approximately frequency-doubled wavelength (FDW). Nonlinear frequency-conversion also allows for limited wavelength tuning of the FDW. As an example, the output from a nonlinear fiber amplifier is frequency-converted. By controlling the polarization state in the nonlinear fiber amplifier and by operating in the soliton-supporting dispersion regime of the host glass, an efficient nonlinear pulse compression for the SW is obtained. The generated pulse width is optimized by utilizing soliton compression in the presence of the Raman-self-frequency shift in the nonlinear fiber amplifier at the SW. High-power pulses are obtained by employing fiber amplifiers with large core-diameters. The efficiency of the nonlinear fiber amplifier is optimized by using a double clad fiber (i.e., a fiber with a double-step refractive index profile) and by pumping light directly into the inner core of this fiber. Periodically poled LiNbO3 (PPLN) is used for efficient conversion of the SW to a FDW. The quality of the pulses at the FDW can further be improved by nonlinear frequency conversion of the compressed and Raman-shifted signal pulses at the SW. The use of Raman-shifting further increases the tuning range at the FDW. For applications in confocal microscopy, a special linear fiber amplifier is used.

The present invention relates to an apparatus for producing optical pulses of a desired wavelength. The apparatus includes an optical pulse source operable to generate input optical pulses at a first wavelength. The apparatus further includes a higher-order-mode (HOM) fiber module operable to receive the input optical pulses at the first wavelength, and thereafter to produce output optical pulses at the desired wavelength by soliton self-frequency shift (SSFS). The present invention also relates to a method of producing optical pulses having a desired wavelength. This method includes generating input optical pulses using an optical pulse source, where the input optical pulses have a first wavelength and a first spatial mode. The input optical pulses are delivered into an HOM fiber module to alter the wavelength of the input optical pulses from the first wavelength to a desired wavelength by soliton self-frequency shift (SSFS) within the HOM fiber module, thereby producing output optical pulses having the desired wavelength.

A laser producing high energy ultrashort laser pulses comprises a normal dispersion segment, a gain segment, an anomalous dispersion segment with negligible nonlinearity and an effective saturable absorber arranged to form a laser cavity. Each segment is optically interconnected so that a laser pulse will propagate self-similarly therein. (A pulse that propagates in a self-similar manner is sometimes referred to as a “similariton.”) With this laser the limitations of prior art laser oscillators are avoided. Also provided are means for pumping the gain medium in the laser cavity, and means for extracting laser pulses from the laser cavity. The laser cavity is preferably a ring cavity. Preferably the laser is configured to achieve unidirectional circulation of laser pulses therein. This configuration is scalable to much higher pulse energy than lasers based on soliton-like pulse shaping.

A passively mode-locked solid-state laser is designed to emit a continuous-wave train (51, 52) of electromagnetic-radiation pulses, the fundamental repetition rate of the emitted pulses exceeding 1 GHz, without Q-switching instabilities. The laser includes an optical resonator (3.1), a solid-state laser gain element (2) placed inside the optical resonator (3.1), a device (1) for exciting said laser gain element (2) to emit electromagnetic radiation having the effective wavelength, and a device (4) for passive mode locking including a saturable absorber. The laser gain element (2) is a laser material with a stimulated emission cross section exceeding 0.8×10−18 cm2 at the effective wavelength, and is made of Nd:vanadate. The saturable absorber (4) is preferably a semiconductor saturable absorber mirror (SESAM) device. Even higher repetition rates are achieved by operating the laser in the soliton regime. For use in fiber-optical telecommunication, the laser wavelength is preferably shifted to 1.5 μm by use of an optical parametric oscillator. The laser is simple, robust, compact, efficient, and low-cost. It generates a relatively large average power of 100 mW and higher, which is useful for a number of optical probing and detection applications, in a beam (51, 52) that is substantially a fundamental spatial mode.

The invention concerns a wavelength-division multiplex soliton signal fiber optic transmission system; to reduce the effects of collision jitter on the soliton channels, it proposes quasi-distributed amplification combining lumped amplification and distributed amplification. In this way it is possible to combine pumping of a lightly doped line fiber an dumped amplification by an EDFA in the repeaters. Reduncant and common pumping means are advantageously used for the lumped amplification and the distributed amplification and the gain of the lumped amplification is advantageously controlled automatically.

The present invention relates to using spin transfer torque underneath a nanocontact on a magnetic thin film with perpendicular magnetic anisotropy (PMA), provides generation of dissipative magnetic droplet solitons and magnetic droplet-skyrmions and report on their rich dynamical properties. Micromagnetic simulations identify the conditions necessary to nucleate and drive droplet-skyrmions over a wide range of currents and fields. Micromagnetic simulations also demonstrate how droplets and droplet-skyrmions can be used as skyrmion injectors and detectors in skyrmion-based magnetic memories. The droplet-skyrmion can be controlled using both current and magnetic fields, and is expected to have applications in spintronics, magnonics, skyrmionics, and PMA-based domain-wall devices.

A method of regenerating non-soliton RZ optical signals, the method including the steps of: a compression step, whereby the RZ signals are compressed into soliton-type signals; a modulation step whereby synchronous optical modulation is performed on the soliton-type signals, by using a clock; and a decompression step whereby the modulated soliton signals are decompressed into non-soliton RZ signals. The method makes it possible to apply soliton modulation techniques to non-soliton RZ links, so as to increase the data rate or the transmission length of such inks without inducing errors, and without having to modify the transmission medium. The invention also relates to a regenerator operating using the method. It is also possible to apply the method to NRZ signals, by converting them into RZ signals. The invention is also applicable to multiplexed RZ or NRZ signals.

An optical regeneration system for regenerating a degenerated signal light, comprising a regeneration device having at least one of a soliton converter, a pulse roller, a Kerr-shutter and a soliton purifier. The solilton converter uses an anomalaous-dispersion fiber (ADF) having a fiber length up to three times the soliton frequency, and the pulse roller is provided with a pulse roller fiber having high non-linear characteristics. The Kerr-shutter comprises an optical LO (local oscillation) generator for generating an optical LO on an OPLL (optical phase locked loop), a phase comparator for detecting the phase difference between an externally-input signal light and an optical LO, and a control unit for regulating the repeated frequency of an optical LO based on the phase difference. The soliton purifier has a soliton fiber disposed between two optical fibers.

The invention provides a spacing-adjustable soliton optical frequency comb system based on a micro nano resonant cavity and an adjusting method thereof. The adjusting method comprises three steps of amplifying an after-filtering pumping micro nano resonant cavity by means of a single light source, finding out a wavelength range of the pumping light which can be coupled and enter the micro nano resonant cavity, and determining wavelength range of a corresponding bistable area which is generated by solitons; generating an optical frequency comb by a single-light-source pumping resonance cavity of which the wavelength is a corresponding value when an in-chamber power which is recorded in the first step begins to increase; and finally adjusting the wavelength of the single-light-source in the second step to the wavelength which corresponds with a bistable area, simultaneously adding another light source of which the wavelength is lower than N-time FSR of the light source, coupling the two light sources in the resonant cavity, and obtaining the soliton optical frequency comb through gradual evolution. When the frequency interval of the pumping light source is N-time FSR, the spectral line interval of the soliton optical frequency comb is N-time FSR correspondingly. The distance-adjustable soliton optical frequency comb system can generate the soliton optical frequency comb with adjustable spectral line spacing and realizes no consideration for pumping light wavelength adjusting rate.

A signal processing apparatus, being configured for transmitting and receiving coherent parallel optical signals, comprises a transmitter apparatus including a first single soliton micro-resonator device and a modulator device, wherein the first single soliton micro-resonator device is adapted for creating a single soliton providing a first frequency comb, wherein the first frequency comb provides a plurality of equidistant optical carriers with a frequency spacing corresponding to a free spectral range of the first single soliton micro-resonator device, and the modulator device is adapted for modulating the optical carriers according to data to be transmitted, and a receiver apparatus including a coherent receiver device with a plurality of coherent receivers and a local oscillator device providing a plurality of reference optical signals, wherein the coherent receiver device and the local oscillator device are arranged for coherently detecting the transmitted modulated optical carriers, wherein the signal processing apparatus further includes at least one second single soliton micro-resonator device having a free spectral range being equal or approximated to the free spectral range of the first single soliton micro-resonator device and being adapted for creating at least one single soliton providing at least one second frequency comb, wherein the at least one second frequency comb provides at least one of additional optical carriers and the reference optical signals. Furthermore, a signal processing method, including transmitting and receiving coherent parallel optical signals via a communication channel is described.

A photonic-crystal fiber provides dispersion compensation in a soliton fiber laser. The anomalous dispersion provided by the photonic-crystal fiber permits construction of a femtosecond fiber laser at 1 μm wavelength without prisms or diffraction gratings. The laser produces ˜100-fs pulses with 1 nJ energy, and is a major step toward environmentally-stable all-fiber devices at 1 μm.

The present invention provides a pulse train generator comprising: a dual-frequency signal light source for generating a dual-frequency signal; a soliton shaper for soliton-shaping output light from the dual-frequency signal light source; and an adiabatic soliton compressor for performing adiabatic soliton compression on output light from the soliton shaper, and also provides a waveform shaper used in this pulse train generator, including a plurality of highly nonlinear optical transmission lines and a plurality of low-nonlinearity optical transmission lines which has a nonlinearity coefficient lower than that of the plurality of highly nonlinear optical transmission lines and which has a second-order dispersion value of which an absolute value is different from that of the plurality of highly nonlinear optical transmission lines. Further, the present invention provides a light source comprising a plurality of continuous light sources of which at least one oscillates in a multimode; a multiplexer for multiplexing output light from the continuous light sources; and a nonlinear phenomenon producer for producing a nonlinear phenomenon on output light from the multiplexer so as to suppress SBS (Stimulated Brillouin Scattering).

A soliton air mattress includes an array of air bladder cells that are individually inflatable to quiescent pressure levels which provide comfortable support for a human body, and a soliton wave generator including an air pressure-pulse generator controlled by a wave sequence generator for introducing into ordered sequences of air bladder cells a wave-like time sequence of air pressure pulses which vary quiescent pressure levels in the cells, the pressure wave resulting in a soliton traveling wave of body support force reduction which traverses surfaces of the air bladder cells, thus reducing normal forces exerted on a body and minimizing the occurrence rate of shear forces exerted on the body, thereby inhibiting formation of bedsores. The soliton wave patterns may optionally simulate water waves and / or rocking motions of a boat to produce relaxing effects.

An apparatus and method for producing optical pulses of a desired wavelength utilizes a section of higher-order-mode (HOM) fiber to receive input optical pulses at a first wavelength, and thereafter produce output optical pulses at the desired wavelength through soliton self-frequency shifting (SSFS) or Cherenkov radiation. The HOM fiber is configured to exhibit a large positive dispersion and effective area at wavelengths less than 1300 nm.

A laser producing high energy ultrashort laser pulses comprises a normal dispersion segment, a gain segment, an anomalous dispersion segment with negligible nonlinearity and an effective saturable absorber arranged to form a laser cavity. Each segment is optically interconnected so that a laser pulse will propagate self-similarly therein. (A pulse that propagates in a self-similar manner is sometimes referred to as a “similariton.”) With this laser the limitations of prior art laser oscillators are avoided. Also provided are means for pumping the gain medium in the laser cavity, and means for extracting laser pulses from the laser cavity. The laser cavity is preferably a ring cavity. Preferably the laser is configured to achieve unidirectional circulation of laser pulses therein. This configuration is scalable to much higher pulse energy than lasers based on soliton-like pulse shaping.

The invention provides a regenerator for very high rate solitons, the regenerator comprising a non-linear loop mirror or NOLM receiving the soliton signal and modulating it with a control signal. The regenerator also comprises a device for generating the control signal by beats between two light sources, with the frequency of at least one of the two sources being variable and servo-controlled as a function of the modulated soliton signal, e.g. as a function of its power, or servo-controlled by means of an optical phase-lock loop. This provides a soliton regenerator in which the electronic components operate at low frequency only, while being capable of regenerating a soliton signal at a very high rate.

A method of generating light pulses including pumping laser pulses with a pump laser source, coupling the laser pulses into a pulse guiding medium having an anomalous group-velocity dispersion and a Kerr nonlinearity, and propagating the laser pulses along the pulse guiding medium, wherein soliton-shaped light pulses are formed from the laser pulses within the pulse guiding medium and, resulting from a photoionization of the pulse guiding medium by the light pulses, the light pulses are subjected to a frequency, wherein the method further includes setting the pump laser source and the pulse guiding medium such that the light pulses are fundamental soliton light pulses propagating in the pulse guiding medium, wherein the group-velocity dispersion of the pulse guiding medium being selected such that a ratio of the dispersion and the Kerr nonlinearity decreases with increasing frequency and the fundamental soliton light pulses are compressed with the frequency shift.

The invention relates to an optical frequency comb, and specifically relates to a deterministic optical soliton frequency comb generation system and method based on a micro-cavity. The system comprises a pump laser system, an auxiliary laser system, a packaged micro-cavity resonant cavity, and a temperature controller. The pump laser system and the auxiliary laser system consist of a narrow line width laser with the fixed wavelength or adjustable wavelength, a light amplifier, a polarization controller and an optical circulator. The temperature control system consists of a semiconductor coolerand a controller of the semiconductor cooler, or consists of an on-chip integrated metal lien and a current control system. The system employs the temperature tuning for the position of the harmonicpeak of the micro-cavity resonant cavity, achieves the deterministic generation of a micro-cavity optical soliton frequency comb. According to the scheme provided by the invention, the system is simple in structure, is low in cost, and is high in operability, solves a problem of the dependence on a high-frequency device in a generation process of the micro-cavity optical soliton frequency comb, and has a high practical value in the application field of the micro-cavity optical soliton frequency comb in future.

An optical fiber transmission system for soliton signals with wavelength multiplexing in which the bit times of the various channels lambd1 to lambdn of the multiplex are substantially synchronous, at least at one point. At least one saturable absorber is located at this point. The channels can be made synchronous by an appropriate selection of wavelengths, or by using optical delay lines, or the like. The saturable absorber then modulates the intensity of the soliton signals in the various channels of the multiplex. It is possible to use a clock for remotely driving the saturable absorber. The invention also relates to a corresponding transmission method. The invention makes it possible to transmit over long distances without using active components.

An apparatus and method for producing optical pulses of a desired wavelength utilizes a section of higher-order-mode (HOM) fiber to receive input optical pulses at a first wavelength, and thereafter produce output optical pulses at the desired wavelength through soliton self-frequency shifting (SSFS) or Cherenkov radiation. The HOM fiber is configured to exhibit a large positive dispersion and effective area at wavelengths less than 1300 nm.

In view of the demand of microwave photonics, astronomical spectrometric measurement and parallel optical fiber communication systems for a high-frequency spaced optical frequency comb source, especially the demand for an optical frequency comb source which can be integrated on a chip, the invention provides an optical soliton crystal optical frequency comb generation system and method based on amicro-ring resonator. The system includes a pump laser, an optical amplifier, a polarization controller, an optical frequency comb generator and a temperature controller which are sequentially connected through a single-mode optical fiber. The output wavelength of the pump laser is in accordance with the wavelength of a required optical frequency comb, and the operating wavelength of the optical amplifier is in accordance with the output wavelength of the pump laser. The polarization controller is a polarization controller which can withstand the power of the pump light signal. The optical frequency comb generator includes a package shell, a micro-ring resonator and a temperature regulator. The micro-ring resonator and the temperature regulator are packaged in the package shell. The working temperature of the micro-ring resonator is controlled by the temperature controller which is set outside the package shell and connected with the temperature regulator. The optical soliton crystal optical frequency comb generation system has the advantages of low cost, high reliability and small size.

Methods and systems for delivery of high peak power optical pulses through optical fiber are disclosed. Raman soliton generation is utilized to maintain the properties of the pulses in the delivery fiber. The apparatus can comprise any high peak power pulse source and delivery fiber supporting Raman soliton generation.

The present invention concerns a multiple soliton comb generation method comprising the steps of:providing a single optical resonator configured to support a plurality of distinct spatial modes in which light can propagate;providing an optical pump laser source;simultaneously optically pumping a plurality of distinct spatial modes of the single optical resonator to simultaneously generate independent soliton states in the distinct spatial modes and generate a plurality of frequency combs.

The invention relates to an all-optical quantification system and an all-optical quantification method based on dynamic spectrum compression. The all-optical quantification system comprises a high-nonlinearity optical fiber for converting an optical signal subjected to all-optical sampling into an optical pulse signal subjected to frequency shifting, a dynamic power equilibrium unit for performing power equilibrium on optical pulses with different wavelengths of the optical pulse signal and acquiring an optical pulse signal subjected to power equilibrium, a comb-shaped optical fiber for performing spectrum compression on the optical pulse signal subjected to power equilibrium and thus acquiring an optical signal subjected to spectrum compression, and a dispersion element for performing space separation on the signal subjected to spectrum compression and thus acquiring an quantified signal, wherein the high-nonlinearity optical fiber, the dynamic power equilibrium unit, the comb-shaped optical fiber and the dispersion element are sequentially connected. The all-optical quantification system has the advantages that the shortcomings of three pulse spectrum compression methods in the background technology are effectively overcome, the all-optical qualification precision is also improved, and the complexity of the all-optical quantification system based on soliton self frequency shifting (SSFS) is reduced; and the blank of a dynamic power control part in an all-optical analog to digital converter (ADC) is made up.

The invention relates to an optoelectronic device for generating a frequency comb comprising a laser source (2), a ring microresonator (3) comprising a resonant ring (20) made of a third order optically non-linear material with abnormal dispersion regime. It also comprises a spectral tuning device comprising a junction guide (30) coupled to the resonant ring, electrical biasing means (40) adapted to apply an electrical voltage to the junction, and a control unit (42) adapted to modify the value of the electrical voltage until at least one dissipative temporal soliton is formed in the resonant ring.

The present invention provides a soliton optical frequency comb generation device and an operation method thereof. The device comprises an adjustable pulse laser, a first connection optical fiber, anoptical amplifier, a second connection optical fiber, a polarization controller, a third connection optical fiber, a first circulator, an assistant test output optical fiber, a fourth connection optical fiber, a ceramic ferrule microcavity, single-layer grapheme, an output optical fiber, a first C-type ceramic tube and a second C-type ceramic tube. The device employs the single-layer grapheme andthe FP microcavity structure to generate a soliton optical frequency comb with 10GHz frequency comb intervals in a condition without tuning of the pump laser frequency, and therefore, the soliton optical frequency comb generation device and the operation method thereof are high in integration level, low in power consumption, simple and convenient to operate and good in output result repeatability.

An optical top-hat pulse generator comprising a polarization-maintaining fiber loop and controlled by solitons. A polarization-maintaining coupler launches a continuous wave optical signal into the fiber loop along a principal axis of the fiber loop. Another coupler launches a control pulse into the fiber loop along another orthogonal principal axis. The fiber loop may consist of a plurality of sections of polarization-maintaining fiber spliced together so that the principal axis of one section aligns with the orthogonal principal axis of an adjacent section and the length of each individual section is chosen to achieve equal in magnitude, but opposite in sign group delays between the continuous wave optical signal and the control pulse.

A multiple wavelength light source generates an output signal having a comb of accurately spaced apart frequencies with variable free spectral range in the C-band of optical fiber communication. The light source employs an electro-optical modulator (EOM) driven by a signal generator which modulates with EOM with multiple modulation frequencies to widen the output spectrum of signal. The EOM has a crystal provided with a waveguide. The waveguide may be doped with a rare-earth metal to impart gain properties to equalize the intensities of the comb. In one preferred embodiment, Er, Yt or other doping elements provide the gain property to waveguides. The crystal is also provided with periodically poled structure, and this may be engineered so as to form domains of unequal widths to improve the efficiency of modulation. The output signal from the light source may be split and presented to a bank of filters to create a multiple signals, each signal having one of the spaced apart frequencies. The output signals may be used as channels to be modulated by data and then combined in dense wavelength division multiplexing system, or may be used as a soliton source in time-division multiplexed communication systems.

At a receiver a 20 Gbit / s soliton bit stream (20) is demultiplexed into two 10 Gbit / s bit streams (22a, 22b) using a 2-way splitter (6), a clock extraction circuit (4), and a pair of polarization insensitive amplitude modulators (8a, 8b) exhibiting positive chirp. The outputs of the modulators are fed to detectors (7a, 7b) via lengths (9a, 9b) of optical fiber exhibiting normal dispersion thereby producing bit streams (23a, 23b) with increased mark / space ratio and reduced timing jitter.

The invention discloses a bi-directional mode-locked multi-state soliton fiber laser, belonging to the laser field, which comprises a pump source and a bi-directional ring resonant cavity formed by connecting a wavelength division multiplexer, a gain medium, a fiber chirped grating, an optical circulator, a polarization controller, an optical coupler and a saturable absorber. The pump source is used as the laser energy source and the gain medium is used to provide the gain for the generation of pulsed laser. The saturable absorber is used to realize the mode-locked operation of the laser. Thefiber chirped grating has two input reflection ports, which can compensate the positive dispersion and the negative dispersion respectively. The Optical circulator and optical coupler are used to couple fiber chirped grating to construct bidirectional transmission optical path with different dispersion distribution. With the help of polarization controller, the local polarization state of the laser can be changed, and the state of the mode-locked laser can be adjusted and switched. The bi-directional mode-locked multi-state soliton fiber laser of the invention can bidirectionally transmit andobtain mode-locked laser pulses respectively, and simultaneously provides multi-state soliton laser output.