Optical frequency combs are used for a wide range of applications, some of which require precise control of the amplitude and phase of individual comb teeth. A technique is provided for tooth-level optical frequency comb control. A frequency comb may include a plurality of comb teeth that are separated from one another by a comb frequency spacing. This technique includes generating a train of control pulses, each of the control pulses being frequency-locked to a corresponding tooth of an optical frequency comb to be controlled. The tooth-level control of the frequency comb is enabled via stimulated Brillouin scattering using the train of control pulses.

A laser system is provided. The laser system comprises: a seed laser configured to produce a sequence of seed light pulses, wherein the sequence of seed light pulses are produced with variable time intervals in a sweep cycle; a pump laser configured to produce pump light having variable amplitude in the sweep cycle; and a control unit configured to generate a command to the pump laser to synchronize the pump light with the sequence of seed light pulses.

A system has fiber amplifiers that amplify a seed signal into a high power signal. Control circuity drives the fiber amplifiers. An auxiliary broad-linewidth signal can be selectively introduced to mitigate the onset of Stimulated Brillouin Scattering (SBS) when the primary input seed source does not meet the requirements of power and/or linewidth. To determine whether to mitigate SBS, an input photodiode can detect the seed signal, and the control circuity can detect an operational parameter associated with a detected signal indicative of an onset of SBS on the optical path. In response to the detection, the control circuitry introduces an auxiliary broad-linewidth signal from a broad-linewidth source, which can mitigate the onset of SBS on the optical path.

An optical fiber amplifier compatible with a small form-factor pluggables (SFP+) package includes a housing, and a circuit device and an optical path device that are disposed in the housing, where the housing includes a structure compatible with an SFP+ package and is provided with an accommodation space; both the circuit device and the optical path device are located in the accommodation space, and the optical path device is located below the circuit device; the circuit device is provided with a card edge connector, and the card edge connector can be exposed outside the housing. The optical fiber amplifier compatible with an SFP+ package has a compact internal space. The amplifer has an appearance compatible with a standard SFP+ package. An electrical interface pin also meets a requirement of an existing SFP+ package, and dynamic plugging and plug-and-play can be satisfied.

A method for amplifying an ultrashort laser pulse includes: a) stretching the ultrashort laser pulse in time, b) amplifying the time-stretched laser pulse, c) compressing the amplified time-stretched laser pulse, with at least one gain phase contribution selected from a group consisting of a gain dynamics phase contribution of the laser pulse that emerges as a change in a nonlinear phase on account of gain dynamics in step b), a gain bandwidth phase contribution of the laser pulse that emerges as a change in the nonlinear phase on account of a gain bandwidth in step b), and a combination thereof, being compensated by virtue of d) an additional phase contribution being imparted on the laser pulse prior to step c) and/or e) a spectrum of the laser pulse being changed, in such a way that the at least one gain phase contribution is compensated after step c).

Incoherently combining light from different lasers while maintaining high brightness is challenging using conventional fiber bundling techniques, where fibers from different lasers are bundled adjacently in a tight-packed arrangement. The brightness can be increased by tapering the tips of the bundled fibers to match a single, multi-mode output fiber, e.g., one whose core that is just wide enough to fit the input cores. This increases the brightness of the beam combining. In addition, reducing the outer diameters of the signal fiber claddings allows the signal fibers to be bundled closer together, making it possible to couple more signal fiber cores to the core of a multi-mode output fiber. Similarly, reducing the outer diameter of the pump fiber cladding and/or etching away corresponding portions of the signal fiber cladding in a pump/signal combiner makes it possible to couple more pump light into the signal fiber cladding, again increasing brightness.

An apparatus for combining a plurality of coherent laser beams includes a splitting device for splitting an input laser beam into the plurality of coherent laser beams, a plurality of phase setting devices for adjusting a respective phase of one of the coherent laser beams, and a beam combining device for combining the coherent laser beams, which emanate from a plurality of grid positions of a grid arrangement, to form at least one combined laser beam. The beam combining device has a microlens arrangement with exactly one microlens array for forming the at least one combined laser beam.

A broadband optical amplifier for operation in the 2 μm visible wavelength band is based upon a single-clad Tm-doped fiber amplifier (TDFA). A compact pump source uses a combination of low-power laser diode with a fiber laser to provide a multi-watt pump beam without needing to include thermal management and/or pump wavelength stability components. The broadband optical amplifier is therefore able to be relatively compact device with fiber coupled output powers of >0.5 W CW, high small signal gain, low noise figure, and large OSNR, important for use as a versatile wideband preamplifier or power booster amplifier.

A broadband optical amplifier for operation in the 2 μm visible wavelength band is based upon a single-clad Ho-doped fiber amplifier (HDFA). A compact pump source uses a combination of discrete laser diode with a fiber laser (which may be a dual-stage fiber laser) to create a pump output beam at a wavelength associated with creating gain in the presence of Ho ions (an exemplary pump wavelength being 1940 nm). The broadband optical amplifier may take the form of a single stage amplifier or a multi-stage amplifier, and may utilize a co-propagating pump and/or a counter-propagating pump arrangement.

An amplified hollow-core fiber (HCF) optical transmission system for low latency communications. The optical transmission system comprises a low-latency amplified HCF cable. The low-latency amplified HCF cable comprises multiple HCF segments (or HCF spans). Between consecutive HCF segments, the system comprises low-latency remote optically pumped amplifiers (ROPAs). Each ROPA comprises a gain fiber, a wavelength division multiplexing (WDM) coupler, and an optical isolator. Preferably, the ROPAs are integrated into the HCF cable. Each ROPA is pumped by a remote optical pump source, which provides pump light to the gain fiber. The gain fiber receives an optical transmission signal from the HCF. The WDM coupler combines the pump light with the optical transmission signal, thereby allowing the gain fiber to amplify the optical transmission signal to an amplified transmission signal. The amplified signal is transmitted to another HCF segment through the optical isolator.