An optical apparatus includes one or more pump sources situated to provide laser pump light, and a gain fiber optically coupled to the one or more pump sources, the gain fiber including an actively doped core situated to produce an output beam, an inner cladding and outer cladding surrounding the doped core and situated to propagate pump light, and a polymer cladding surrounding the outer cladding and situated to guide a selected portion of the pump light coupled into the inner and outer claddings of the gain fiber. Methods of pumping a fiber sources include generating pump light from one or more pump sources, coupling the pump light into a glass inner cladding and a glass outer cladding of a gain fiber of the fiber source such that a portion of the pump light is guided by a polymer cladding surrounding the glass outer cladding, and generating a single-mode output beam from the gain fiber.

A laser apparatus includes: a monitoring device that includes a detector that detects light belonging to a first wavelength range including a peak wavelength of at least one of Stokes light and anti-Stokes light, in preference to light belonging to a second wavelength range; and a multi-mode fiber. The Stokes light and the anti-Stokes light result from, in the multi-mode fiber that guides laser light, four-wave mixing in which a plurality of guide modes are involved.

In an example, an apparatus to tandem pump a fiber laser or fiber amplifier may include a combiner; a power amplifier or a power oscillator, or a combination thereof, coupled to an output of the combiner; a seed laser to output light to the power amplifier or the power oscillator, or the combination thereof, via the combiner; and a tandem pump to generate light of a pump source signal, wherein the light of the pump source signal is output to the combiner to cladding pump the power amplifier or the power oscillator, or the combination thereof. Other embodiments may be disclosed and/or claimed.

Methods and system to provide high power and brightness display and illumination systems and methods. In embodiments multi-wavelength laser beams in the wavelength range of 300 nm to 700 nm, including high power beams in these wavelengths having excellent beam qualities are provided and used. The three wavelengths can be primary colors, red, green and blue. Manufacturing and display systems, allowing the high-power white light generation directly from a single fiber laser source, such as theaters, sporting events, public events, private and home entertainment to name a few. The systems are configured for Photopic and Scotopic vision.

Methods and apparatuses for manipulating and modulating of laser beams. The methods and apparatuses enable activating and deactivating of laser beams, while the laser systems maintain their operating power. Further, a hybrid pump module configured to be coupled to an optical fiber having a core and at least one clad, comprising: at least one focusing lens in optical with the optical fiber; plurality of diode modules, each configured to output a multi-mode beam in optical path with the clad; and at least one core associated module, in optical path with the core, configured to provide selected functions. Further, apparatus and methods configured for frequency doubling of optical radiation.

Disclosed is a submarine network device, comprising a fiber set, a pump laser set, an erbium doped fiber amplifier (EDFA) set, a primary fiber coupler (CPL) set and a secondary CPL set, wherein the primary CPL set comprises N primary CPLs, the secondary CPL set comprises N secondary CPLs, with N being an integer greater than or equal to 3. The fiber set is configured to connect the pump laser set, the primary CPL set, the secondary CPL set and the EDFA set. An input port of each primary CPL in the primary CPL set is at least connected with a pump laser. An output port of each secondary CPL in the secondary CPL set is at least connected with an EDFA. Output ports of each primary CPL in the primary CPL set are respectively connected with two different secondary CPLs that are spaced by a secondary CPL, and input ports of each secondary CPL in the secondary CPL set are respectively connected with two different primary CPLs that are spaced by a primary CPL.

A fiber laser system, includes: N fiber laser units that generates respective laser beams, where N2; an output combiner that: combines the respective laser beams, and generates output light including, as the respective laser beams, laser beams different from each other in terms of NA power cumulative distribution; and a control unit that sets a power of each of the respective laser beams such that an upper limit NA corresponding to each of not more than (N1) predetermined power cumulative rate(s) is equal to a specified value for the output light.

Stimulated Brillouin scattering (SBS) limits the maximum power in fiber lasers with narrow linewidths. SBS occurs when the power exceeds a threshold proportional to the beam area divided by the effective fiber length. The fiber lasers disclosed here operate with higher SBS power thresholds (and hence higher maximum powers at kilohertz-class linewidths) than other fiber lasers thanks to several techniques. These techniques include using high-absorption gain fibers, operating the laser with low pump absorption (e.g., 80%), reducing the length of un-pumped gain fiber at the fiber output, foregoing a delivery fiber at the output, foregoing a cladding light stripper at the output, using free-space dichroic mirrors to separate signal light from unabsorbed pump light, and using cascaded gain fibers with non-overlapping Stokes shifts. The upstream gain fiber has high absorption and a larger diameter for high gain, and subsequent gain fiber has a smaller diameter to improve beam quality.

Provided are a low-cost and low power-consumption optical fiber amplifier, an optical fiber amplifier control method, and a transmission system. The optical fiber amplifier comprises: an optical fiber to which pumping light is supplied and which amplifies an optical signal, the optical fiber including a plurality of cores in a cladding; a light source which outputs the pumping light; a combining means which supplies the pumping light from the light source to the cladding of the optical fiber and causes the pumping light to be combined with the optical signal; a collect means which collects, without collecting the signal light, pumping light among the supplied pumping light that has not been absorbed by the optical fiber; a monitor means which monitors residual pumping light that has passed through the optical fiber and collected by the collect means; and a control means which controls the state of the pumping light.

The present disclosure relates to systems and methods for reducing thermal effects in double-clad clad optical fiber amplifying systems via control of the pump absorption. One optical fiber amplifying system for reducing thermal effects includes one or more first optical pump sources, each configured to output radiation of a pump wavelength, a bridge optical fiber, having an input configured to receive the radiation of the pump wavelength output by the one or more first optical pump sources and an output, and an active optical fiber that has a first end substantially directly coupled to the output of the bridge optical fiber and a second end. The active optical fiber is configured to amplify radiation of the first active wavelength when pumped with radiation of the pump wavelength.