An apparatus for combining a plurality of coherent laser beams includes a splitting device configured to split an input laser beam into the plurality of coherent laser beams, a plurality of phase setting devices configured to adjust a respective phase of one of the plurality of coherent laser beams, and a beam combining device configured to combine the plurality of coherent laser beams, which emanate from a plurality of grid positions of a grid arrangement. The beam combining device includes a microlens arrangement having at least two microlens arrays. The apparatus further includes a controller configured to adjust a respective phase of a respective one of the plurality of coherent laser beams and/or vary a respective phase of a respective one of the plurality of coherent laser beams.

A rod-type photonic crystal fiber amplifier includes a signal coupling lens, a first dichroic mirror, a first hollow pump coupling lens, and a rod-type photonic crystal fiber. The rod-type photonic crystal fiber comprises a core and a cladding, wherein signal light is coupled into the core of the rod-type photonic crystal fiber through the signal coupling lens, and pump light is coupled into the cladding of the rod fiber through the hollow pump coupling lens. The structure optimizes the coupling between the signal light and the core of the rod-type photonic crystal fiber, and the coupling between the pump light and the cladding of the rod fiber respectively by introducing the hollow pump coupling lens. The purpose of this is to fully optimize the rod-type photonic crystal fiber amplifier, improve the amplification efficiency and improve the efficiency of a manufacturing process.

An electrically tunable non-reciprocal phase shifter, an electrically tunable polarization filter, a NALM mode-locked laser and a Sagnac loop are provided. The electrically tunable non-reciprocal phase shifter includes a modulation crystal device, a birefringent crystal device, a Faraday rotator, and a fiber coupler. The phase shifter is configured to couple two beams of light to a fast axis and a slow axis of the modulation crystal device, respectively; and change a refractive index difference between the fast axis and the slow axis to introduce different phase delays for the two beams of the light, so as to control a non-reciprocal linear phase shift amount between the two beams of the light.

A coherent fiber array laser power projection system scalable to large number of subapertures and includes sensors that produce signals dependent upon beam characteristics, and controllers configured to control beam characteristics to achieve either phasing of outgoing beams at transmitter plane or coherent beam combining at a remote target or both.

A laser system may include one or more seed lasers to generate a pulsed seed beam including one or more laser pulses, 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 pulse pattern generator includes splits the at least one laser pulse from the pulsed seed beam along two or more delay paths and combines light along the two or more delay paths to a common optical path, and where the intermediate patterned burst-mode beam includes laser pulses with a selected pattern of inter-pulse spacings associated with the two or more delay paths. The laser system may further include power amplifiers to amplify the intermediate patterned burst-mode beam to form an amplified patterned burst-mode beam, where the amplified patterned burst-mode beam includes amplified laser pulses with the selected pattern of inter-pulse spacings.

The present disclosure provides an optical system (100) for controlling atoms. The optical system (100) comprises a laser source (10) for generating a laser beam at a carrier frequency and microwave and radio frequency (MW/RF) sources (41 and 45) for generating I and Q modulation signals at a set of frequencies, wherein the set of frequencies comprises at least two frequencies. The optical system (100) further comprises an IQ modulator (20) configured for receiving the laser beam and the generated signals at the set of frequencies and for outputting an output laser beam (Eout) based on the received laser beam and the generated signals at the set of frequencies, wherein the output laser beam (Eout) comprises multi-toned optical single-sidebands (MT-OSSB) at the set of frequencies with the carrier frequency being suppressed.

A method is disclosed for controlling a pulse repetition rate of pulsed laser beam 1 created by pulsed laser oscillator 100, includes generating beam 1 by oscillator 100, splitting beam 1 into first pulsed split beam 1a and second pulsed split beam 1b, time-delaying split beam 1a relative to split beam 1b by optical delay device 220, generating timing baseband signal Sc including a timing jitter of the pulse repetition rate based on split beam 1a and second split beam 1b by timing detector device 230, generating feedback signal Sf based on timing baseband signal Sc, and applying feedback signal Sf on oscillator 100 and controlling the pulse repetition rate of beam 1 based on the feedback signal Sf. Furthermore, repetition rate control apparatus 200 for controlling a pulse repetition rate of pulsed laser oscillator 100 and pulsed laser oscillator 100, comprising repetition rate control apparatus 200 are described.

A gain adjuster, a gain adjustment method, and an optical line terminal are provided, to separately adjust a gain of a to-be-adjusted optical signal. The gain adjuster includes a light spot conversion component and a gain medium that are sequentially coupled. The gain adjuster further includes a pump laser. The light spot conversion component is configured to adjust light spot sizes of at least some optical signals in received optical signals to output a first optical signal transmitted in space. The pump laser is configured to excite the gain medium. The gain medium is configured to adjust a gain of the first optical signal to output a second optical signal.

A collinear T-cavity VECSEL system generating intracavity Hermite-Gaussian modes at multiple wavelengths, configured to vary each of these wavelengths individually and independently. A mode converter element and/or an astigmatic mode converter is/are aligned intracavity to reversibly convert the Gaussian modes to HG modes to Laguerre-Gaussian modes, the latter forming the system output having any of the wavelengths provided by the spectrum resulting from nonlinear frequency-mixing intracavity (including generation of UV, visible, mid-IR light). The laser system delivers Watt-level output power in tunable high-order transverse mode distribution.

Embodiments discussed herein refer to LiDAR systems that use refraction compensation to improve transmission efficiency of light energy through transmissive mediums such as covers. Refraction compensation can be achieved using a cover or an anti-reflective coating.