A laser transmitter assembly for use in a Coherent Doppler Wind Lidar (“CDWL”) system includes a telescope/scanner assembly, a receiver, and a master oscillator crystal and a power amplifier crystal each constructed of Ho:YAG. The crystals are end-pumped to transmit an output beam through the telescope/scanner assembly with a high repetition rate of 200-300 Hz and 35 mJ of energy. As part of the CDWL system, a pump laser end-pumps the master oscillator and power amplifier crystals using a pump beam having a nominal wavelength of 1.905 μm. A seed laser transmits a seeding beam into the master oscillator crystal at a nominal wavelength of 2.0965 μm. The telescope/scanner assembly transmits the generated laser beam through an atmosphere toward a scene of interest, collects a backscattered return signal, and communicates the backscattered return signal to the receiver during operation of the CDWL system.

The invention discloses a preparation method and device of active microcrystalline fiber, place the prefabricated rod in the drawing furnace for wire drawing, the drawn fiber is induced by magnetic field in uncoated state and combined with laser treatment technology, the laser beam is focused on the fiber and recrystallized after laser treatment to obtain active microcrystalline fiber. Appropriate laser processing power directly affects the silicate glass fiber in the crystal structure, type, degree of crystallinity, grain size, content, and how much residual phase of glass. Induced by external magnetic field, the thermodynamics and dynamics of crystallization process are changed, make the crystal size distribution is better and uniform, reduce the phenomenon of condensation and makes the grain size is smaller.

A Holmium-doped fiber amplifier (HDFA) with cascaded pumping is disclosed. The cascaded pumping has at least two pumping stages arranged so that an emission spectrum of a preceding pumping stage at least partly corresponds to an absorption spectrum of the succeeding pumping stage, and the pumping stages are staggered so that an emission spectrum of the last pumping stage at least partly corresponds to an absorption spectrum of the Holmium-doped fiber.

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 laser system may include a seed laser formed from a Ti:Sapphire laser providing pulsed light and an optical parametric amplifier to generate pulsed light within a Holmium emission spectrum as seed pulses in response to the pulsed light from the Ti:Sapphire laser. A laser system may further include an amplifier to generate amplified pulses of light in response to the seed pulses from the seed laser, where the amplified pulses include at least some of the seed pulses amplified by the one or more Holmium-doped gain media pumped by the one or more pump lasers. The amplifier may include one or more Holmium-doped gain media and one or more pump lasers providing continuous-wave pump light within an absorption spectrum of the one or more Holmium-doped gain media.

A laser system may include a laser resonator configured to emit an input laser beam having an elliptical cross-sectional shape. The laser system also may include first reflective device configured to reflect the input laser beam to produce a first reflected laser beam. The first reflective device may include a spherical surface for reflecting the input laser beam. The laser system also may include a second reflective device configured to reflect the first reflected laser beam to produce a second reflected laser beam. The laser system also may include a coupling device configured to focus the second reflected laser beam to produce an output laser beam. The coupling device may include a spherical surface for receiving the second reflected laser beam. The laser system also may include an optic fiber configured to transmit the output laser beam for emission of the output laser beam onto a target area.

A laser system includes a first laser cavity to output a laser light along a first path, a first mirror to receive the laser light from the first laser cavity, and redirect the laser light along a second path that is different than the first path, a second mirror to receive the laser light from the first mirror, and redirect the laser light along a third path that is different than the first path and the second path, a beam splitter located at a first position on the third path, a beam combiner located at a second position on the third path; and a coupling lens assembly, the coupling lens assembly including a lens located at a third position on the third path, wherein the coupling lens assembly moves the lens in x-, y-, and x-directions.

A low wavelength infrared Super Continuum (SC) signal from a master oscillator introduces two or more seeds into an amplifier that supports the Raman effect. A counter-propagating, high-power, continuous wave, or quasi-continuous wave quantum cascade lasers pump (amplifies) a first optical seed creating a cascading amplification of subsequent optical seeds forming two or more tunable wavelength coherent optical pump sources.

A doped fiber amplifier is proposed that includes both a Ho-doped amplifier (used as a preamplifier) and a Tm-doped amplifier (used as a power amplifier). The Ho-doped preamplifier typically uses a single clad (SC) optical fiber as the gain element, with both the propagating signal and pump beam introduced into the Ho-doped core of the SC fiber. The Tm-doped power amplifier typically utilizes a double clad (DC) optical fiber as the gain element, which allows for a multimode pump to propagate within the Tm-doped core region and inner cladding, providing efficient high power amplification of the signal received at its input.

A fiber-based optical amplifier for operation at an eye-safe input signal wavelength λ.sub.S within the 2 μm region is formed to include a section of Holmium (Ho)-doped optical gain fiber. The pump source for the fiber amplifier is particularly configured to provide pump light at a wavelength where the absorption coefficient of the Ho-doped optical gain fiber exceeds its gain coefficient (referred to as an “absorption-dominant pump wavelength”), and is typically within the range of 1800-1900 nm. The selection of an absorption-dominant pump wavelength limits the spontaneous emission of the pump from affecting the amount of gain achieved at the higher wavelength end of the operating region. The amount of crosstalk between the signal wavelength and pump wavelength is also reduced (in comparison to using the conventional 1940 nm pump wavelength).