A measurement system is provided with an array of laser diodes with one or more Bragg reflectors. At least a portion of the light generated by the array is configured to penetrate tissue comprising skin. A detection system configured to: measure a phase shift, and a time-of-flight, of at least a portion of the light from the array of laser diodes reflected from the tissue relative to the portion of the light generated by the array; generate one or more images of the tissue; detect oxy- or deoxy-hemoglobin in the tissue; non-invasively measure blood in blood vessels within or below a dermis layer within the skin; measure one or more physiological parameters based at least in part on the non-invasively measured blood; and measure a variation in the blood or physiological parameter over a period of time.

A laser system includes a laser radiation source for emitting light, and an optical fiber unit that includes an optical fiber. The optical fiber includes a light guiding region, an input coupling end having a first fiber end surface for coupling the light into the light guiding region, and an output coupling end having a second fiber end surface for coupling the light out of the light guiding region. The laser system further includes a coupling device for coupling the light into the optical fiber unit, a reflection element configured to reflect the light coupled out of the light guiding region back toward the second fiber end surface to be coupled back into the light guiding region via the second fiber end surface, and a measuring device configured to capture the light reflected by the reflection element.

A laser system may include one or more seed lasers to generate a pulsed seed beam. The system may further include a pulse pattern generator to generate an intermediate patterned burst-mode beam from at least one laser pulse from the pulsed seed beam, where the intermediate patterned burst-mode beam includes one or more pulse bursts, and where each of the one or more pulse bursts includes a series of laser pulses with a selected pattern of inter-pulse spacings. The system may further include two or more power amplifiers to amplify the intermediate patterned burst-mode beam to form an amplified patterned burst-mode beam, where at least two of the power amplifiers amplify different portions of the intermediate patterned burst-mode beam, and where the amplified patterned burst-mode beam includes a series of amplified pulse bursts including amplified laser pulses with the selected pattern of inter-pulse spacings.

This application discloses an optical amplifier including a Raman fiber amplifier (RFA), a dynamic gain equalizer (DGE), a filter, an erbium-doped fiber amplifier (EDFA), an RFA gain controller, an EDFA gain controller, and an optical amplifier controller. The optical amplifier controller is configured to provide instructions to and receive feedback from the RFA and EDFA gain controllers. The RFA and the EDFA are configured to amplify an optical signal. The RFA gain controller is configured to control the RFA to adjust a gain. The EDFA gain controller is configured to control the EDFA to adjust a gain. The DGE adjusts insertion loss. The filter is configured to filter an amplified spontaneous emission signal produced in an optical amplification process of the RFA.

A fiber laser apparatus includes a pump light source that emits pump light; a pump delivery fiber that guides the pump light; an amplifying optical fiber that is optically coupled to the pump delivery fiber and guides laser light; and a filter element that causes more loss of light of a wavelength range that includes a peak wavelength of at least one of Stokes light and anti-Stokes light than the laser light. The Stokes light and anti-Stokes light result from four-wave mixing involving a plurality of guide modes in a multi-mode fiber that guides the laser light. The filter element is disposed between: the pump delivery fiber and the amplifying optical fiber, the amplifying optical fiber and the multi-mode fiber, or at the multi-mode fiber.

Signal combined optical fiber devices, systems, and methods for reducing signal spectrum pumping of Raman spectrum. Power of a Raman component in an output of a signal combined fiber laser system may be reduced by diversifying peak signal wavelengths across a plurality of signal generation and/or amplification modules that are input into a signal combiner. In some examples, fiber laser oscillators that are to have their output signals combined to reach a desired cumulative system output power are tuned to output signal bands of sufficiently different wavelengths that signal from separate ones of the oscillators do not collectively pump a single Raman band. With the combined signal component comprising different peak signal wavelengths, the Raman component of combined output may have multiple peak wavelengths and significantly lower power than in systems where signals of substantially the same signal peak wavelength are combined.

A method for adjusting a laser beam includes, following passage of the laser beam through a beam-shaping device, measuring, via a detector of a detector device, a beam profile of the laser beam. The method further includes determining a beam quality property of the laser beam based on the measured beam profile and altering an adjustable optical unit for modifying at least one property of the laser beam prior to the entry into the beam-shaping device. For adjusting the laser beam, the adjustable optical unit is altered based on the determined beam quality property.

In some implementations, an amplifier device may include a first amplifier configured to amplify signals in a first range of optical wavelengths. The first amplifier may include a first portion that includes one or more first optical gain components, and a second portion that includes one or more second optical gain components and a variable optical attenuator. The amplifier device may include a second amplifier configured to amplify signals in a second range of optical wavelengths. The amplifier device may include a filter for the first range of optical wavelengths and the second range of optical wavelengths. The filter may be located between the first portion and the second portion of the first amplifier.

A hybrid optical amplifier is proposed that includes a preamplifier element formed of single-clad Ho-doped optical fiber and a power amplifier element formed of single-clad Tm-doped (or Tm—Ho co-doped) optical fiber. The preamplifier is used to impart gain to an input signal propagating at a wavelength λ.sub.S in the presence of a first pump beam operating at λ.sub.P1, creating an amplified output over a defined transmission bandwidth. The power amplifier element is disposed at the output of the preamplifier element and provides an additional level of gain to the output of the preamplifier element in the presence of a second pump beam operating at λ.sub.P2. A passband filter may be used between the preamplifier and the power amplifier to ensure that only wavelength components within the defined transmission bandwidth are applied as an output to the power amplifier.

A low-repetition-rate (10-Hz), picosecond (ps) optical parametric generator (OPG) system produces higher energy output levels in a more robust and reliable system than previously available. A picosecond OPG stage is seeded at an idler wavelength with a high-power diode laser and its output at ˜566 nm is amplified in a pulsed dye amplifier (PDA) stage having two dye cells, resulting in signal enhancement by more than three orders of magnitude. The nearly transform-limited beam at ˜566 nm has a pulse width of ˜170 ps with an overall output of ˜2.3 mJ/pulse. A spatial filter between the OPG and PDA stages and a pinhole between the two dye cells improve high output beam quality and enhances coarse and fine wavelength tuning capability.