Bismuth (Bi) doped optical fibers (BiDF) and Bi-doped fiber amplifiers (BiDFA) are shown and described. The BiDF comprises a gain band and an auxiliary band. The gain band has a first center wavelength (λ1) and a first six decibel (6 dB) gain bandwidth. The auxiliary band has a second center wavelength (λ2), with λ2>λ1. The system further comprises a signal source and a pump source that are optically coupled to the BiDF. The signal source provides an optical signal at λ1, while the pump source provides pump light at a pump wavelength (λ3).

A fiber amplifier that is particularly configured to provide gain across a large extent of the C-band spectral range (i.e., a gain bandwidth of at least 42 nm, preferably within the range of 46-48 nm) utilizes a specially-designed discrete Raman amplifier in combination with a high inversion level EDFA to extend the gain bandwidth of a conventional EDFA C-band optical amplifier, while maintaining the gain ripple below an acceptable value. The EDFA provides operation at a highly-inverted level and the specialized discrete Raman amplifier (sDRA) element has particular parameters (dispersion, length, effective area) selected to maintain operation within a “small gain” regime while also extending the long wavelength edge of the gain bandwidth and reducing the gain ripple attributed to the EDFA component.

A method of manufacturing an optical fiber is provided. The method involves providing a fiber preform with an active core and a pump-guiding cladding, and assembling one or more side rods to the fiber preform. The side rods extend longitudinally along an outer surface of the pump-guiding cladding. The resulting fiber preform assembly is drawn into the optical fiber. Each side rod defines a longitudinal protrusion extending along the optical fiber. Each longitudinal protrusion may have a cross-section forming a middle bump projecting radially away from the outer surface of the pump-guiding cladding and smooth transition regions with this outer surface of the pump-guiding cladding on opposite sides of the middle bump.

A fiber includes a core and cladding, both of which may have temperature dependent indices of refraction. The materials and size of the core and cladding may be selected such that as the temperature of the core and/or cladding is heated above room temperature, the fiber transitions from supporting multimode optical waveguiding to supporting single mode waveguiding.

A laser for high power applications. The laser is a lamp driven slab design with a face to face beam propagation scheme and an end reflection that redirects the amplified radiation back out the same input surface. Also presented is a side to side larger amplifier configuration, permitting very high average and peak powers due to the electrical efficiency of absorbing energy into the crystal, optical extraction efficiency, and scalability of device architecture. Cavity filters adjacent to pump lamps convert the unusable UV portion of the pump lamp spectrum into light in the absorption band of the slab laser thereby increasing the overall pump efficiency. The angle of the end reflecting surface is changed to cause the exit beam to be at a different angle than the inlet beam, thereby eliminating the costly need to separate the beams external to the laser with the subsequent loss of power.

Disclosed is a very large mode area single-mode amplifying optical fiber including a doped core having a core diameter larger than 20 micrometers, surrounded by at least a first cladding including a solid matrix made of a first glass and two stress applying parts arranged symmetrically with respect to the core, the two stress applying parts being aligned along an alignment axis, the cladding including two flat surfaces extending parallel to the longitudinal axis and transverse to the alignment axis, the two flat surfaces being joined by two rounded surfaces and wherein the optical fiber is suitable for being bent with a bending diameter less than 30 cm in a plane forming an angle of less than 15 degrees with the alignment axis while having bending losses below 0.5 dB/m.

A fiber includes a core and cladding, both of which may have temperature dependent indices of refraction. The materials and size of the core and cladding may be selected such that as the temperature of the core and/or cladding is heated above room temperature, the fiber transitions from supporting multimode optical waveguiding to supporting single mode waveguiding.

A fiber amplifier that is particularly configured to provide gain across a large extent of the C-band spectral range (i.e., a gain bandwidth of at least 42 nm, preferably within the range of 46-48 nm) utilizes a specially-designed discrete Raman amplifier in combination with a high inversion level EDFA to extend the gain bandwidth of a conventional EDFA C-band optical amplifier, while maintaining the gain ripple below an acceptable value. The EDFA provides operation at a highly-inverted level and the specialized discrete Raman amplifier (sDRA) element has particular parameters (dispersion, length, effective area) selected to maintain operation within a small gain regime while also extending the long wavelength edge of the gain bandwidth and reducing the gain ripple attributed to the EDFA component.

Provided is an optical parametric oscillation laser based on I-type quasi-phase matching. The optical parametric oscillation laser comprises a femtosecond laser pumping source (1), an input coupling mirror (3), an Mg:PPLN crystal (4), an output coupling mirror (7) and a beam splitter prism (12), wherein the femtosecond laser pumping source (1) of a synchronous pump, the input coupling mirror (3), the Mg:PPLN crystal (4), the output coupling mirror (7) and the beam splitter prism (12) are sequentially placed. Group velocity mismatching between near-infrared pump light and intermediate infrared signal light in the intermediate infrared optical parametric oscillation laser is eliminated by using the dispersion relationship between the crystal and the temperature and in a manner of adjusting the working temperature of the crystal, so that an optical parametric oscillation process can satisfy phase matching and group velocity matching at the same time, and therefore intermediate infrared ultrashort pulse laser with high power and wide spectrum is obtained.

A slab laser and its method of use for high power applications including the manufacture of semiconductors and deposition of diamond and/or diamond-like-carbon layers, among other materials. A lamp driven slab design with a face-to-face beam propagation scheme and an end reflection that redirects the amplified radiation back out the same input surface is utilized. A side-to-side amplifier configuration permitting very high average and peak powers having scalability is also disclosed. Cavity filters adjacent to pump lamps convert the normally unusable UV portion of the pump lamp spectrum into light in the absorption band of the slab laser, thereby increasing the overall pump efficiency. The angle of the end reflecting surface is changed to cause the exit beam to be at a different angle than the inlet beam, thereby eliminating the costly need to separate the beams external to the laser with the subsequent loss of power.