A system includes a light transmitter configured to emit a first light beam. The first light beam includes a primary portion and an amplified spontaneous emission (ASE) portion. The system also includes a host material configured to receive the first light beam and emit a second light. The host material is configured to generate the second light by depopulation of chromophores of one or more dopants in the host material caused by energy of the primary portion of the first light beam. The second light is continuous wave and speckle free.

Systems and methods for measuring temperature in an environment by creating a first beam having an energy of about 50 mJ/pulse, and a pulse duration of about 100 ps. A second beam is also created, having an energy of about 2.3 mJ/pulse, and a pulse duration of about 58 ps. The first beam and the second beam are directed into a probe region, thereby expressing an optical output. Properties of the optical output are measured at a sampling rate of at least about 100 kHz, and temperature measurements are derived from the measured properties of the optical output. Such systems and methods can be used to measure temperature in environments exhibiting highly turbulent and transient flow dynamics.

An optical fiber filter includes a fiber core, inner cladding, and outer cladding. A refractive index of the fiber core, a refractive index of the inner cladding, and a refractive index of the outer cladding progressively decrease in sequence. The fiber core is configured to transmit at least two mutually different first optical signal modes, the inner cladding is configured to transmit at least two mutually different second optical signal modes, and at least one fiber grating is etched on the fiber core. At least part of optical power of a target first optical signal mode is coupled to only a target second optical signal mode at the fiber grating. The target first optical signal mode is one of the at least two first optical signal modes, and the target second optical signal mode is one of the at least two second optical signal modes.

A laser system for the generation of ultrashort optical pulses of light including an oscillator emitting low power and negatively chirped optical pulses with a spectral bandwidth W1, a dispersive connecting segment to maintain the sign of the chirp of the pulses of the oscillator, an optical amplifier for amplifying the optical light pulses and a negative group velocity dispersion segment for compensating phase contributions of the whole propagation process. During the propagation from the output of the oscillator to the end of the optical amplifier, the chirp of the light pulses will change once from negative to positive chirp. After a final compression stage ultrashort optical pulses can be generated.

An apparatus is provided, the apparatus comprising: (i) a diode-pumped solid-state laser oscillator configured to generate a pulsed laser beam having predefined beam characteristics corresponding to a current setting selection of a controller; and (ii) an amplifier configured to amplify an energy and modify a beam profile of the pulse laser beam. A beam detector is coupled to the generated beam to monitor a combination of: (i) a beam pulse width; (ii) a beam diameter; and (iii) an energy level, and generates an error signal to be sent back as a feedback signal to the controller. The controller configures the current source to output a correction current to tune the DPSSL oscillator, the wave plate, and the first polarizer to rotate a correction polarization angle and adjust the energy amplification or temporal profile to within a defined performance tolerance.

A femtosecond laser source according to an embodiment of the present invention includes: a pulse generator that converts a continuous wave laser into an optical pulse train; a burst generator that separates the optical pulse train into a plurality of burst pulses; a pulse amplification and spectral broadening unit that expands the spectrum by amplifying a plurality of burst pulses; and a pulse compressor that compresses a plurality of amplified burst pulses to generate a femtosecond laser with a pulse width of 1 picosecond (10.sup.−12 s) or less.

An EHz ultrafast modulated pulse scanning laser and a distributed fiber sensing system. A plurality of phase-shift gratings are engraved on a doped fiber, the phase-shift gratings having different central window wavelengths and a wavelength interval between the adjacent central window wavelengths being a preset fixed value. When a pump light emitted by a pump laser source is coupled by a wavelength division multiplexer and enters the doped fiber, a single-mode narrow-linewidth laser light having multiple wavelengths with a wavelength interval being a preset fixed value can be generated, by using the phase-shift gratings graved on the doped fiber. The ultrafast modulation is completed by using a time-domain control method based on an EOM. An internally frequency converted pulse light formed by splicing pulse lights whose frequencies linearly increase is obtained, thus forming the EHz ultrafast modulation of a distributed feedback fiber laser. In this way, a coherence length of an output laser light is increased while a frequency of the laser light is remained.

Photonic chip includes an external cavity (EC) optical circuit to provide wavelength-selective optical feedback to a length of active optical fiber. Light generated in the active optical fiber may be coupled from the EC circuit to a light processing circuit of the photonic chip, such as an optical modulator or an optical mixer. The EC circuits may include single-frequency and multi-frequency optical filters, which may include ring resonators, dual-ring resonators, and optical modulators to support multi-frequency lasers. The EC circuits may further include pump combiners and optical isolators.

The present invention discloses a grating enhanced distributed vibration demodulation system based on three-pulse shearing interference, comprising: a laser device, a pulse optical modulator, a three-pulse generation polarization-maintaining structure, a first erbium-doped fiber amplifier, a first optical circulator, a fiber grating array, a second erbium-doped fiber amplifier, a second optical circulator, a three-in-three optical coupler, a first Faraday rotator mirror, a second Faraday rotator mirror, and a four-channel data acquisition card, On the basis of a distributed fiber grating vibration sensing system, three-pulse dislocation interference and three-in-three optical coupler digital phase demodulation technologies are adopted, XX and XY pulses are utilized to complement interference visibility, and demodulation is performed by selecting a better path, so that polarization fading resistance and interference signal high visibility in the distributed fiber grating vibration sensing system are realized.

A light source employed in a coherent Raman scattering (CRS) spectroscopic apparatus or a CRS microscope includes a chromium forsterite laser (CrFL), a variable delay optical path configured to delay one optical pulse of branched optical pulses obtained by dividing an optical pulse from the CrFL according to a power, a highly nonlinear waveguide into which the other optical pulse of the branched optical pulses is input, a first wavelength filter connected to an output of the highly nonlinear waveguide, an ytterbium-doped glass fiber optical amplifier (YbFA) connected to an output of the wavelength filter, and a second wavelength filter connected to an output of the YbFA. The light source includes a one-optical path mode in which two wavelength bands corresponding to Raman scattering wavenumbers to be used for measurement are selected from an output of the variable delay optical path, and a two-optical path mode in which an output of the variable delay optical path and an output of the second wavelength filter are time-synchronized.