摘要:
A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.
摘要:
A method is provided for forming an optical fiber amplifier. The method comprises providing a composite preform having a gain material core that includes one or more acoustic velocity varying dopants to provide a longitudinally varying acoustic velocity profile along the gain material core to suppress Stimulated Brillouin Scattering (SBS) effects by raising the SBS threshold and drawing the composite preform to form the optical fiber amplifier.
摘要:
A cladding-pumped gain optical fiber is provided. The cladding-pumped gain optical fiber includes a core transmitting a signal light; a first cladding covering the core and having an optical-gain dopant; a second cladding covering the first cladding for transmitting a pumping light; and a third cladding covering the second cladding for reflecting the pumping light.
摘要:
Systems and devices enabling a highly compact design for a fiber-based lasing and/or amplifying system are disclosed. In some instances, a tightly-coiled active optical fiber may be coupled with a seed source and a pump source for optical amplification and other applications. Such systems can be disposed in a small footprint package such as a butterfly package or a high heat load package. In some instances, the tightly-wound active optical fiber may further include a fiber Bragg grating adapted to accommodate bends in the active optical fiber. The active optical fiber may further utilize a cladding shaped to maintain an orientation of the active optical fiber in relation to a bend in the fiber.
摘要:
Fiber lasers for producing Band I wavelengths include a laser cavity having an optical fiber with specific parameters in length and thickness and doping concentration, and having high reflectivities. Examples show the feasibility of producing such fiber lasers. Fiber lasers for producing Band IV wavelengths include a depolarized laser oscillator, at least one amplifier and a polarizer. Depolarized laser oscillator is an inherently depolarized CW laser, or a depolarized laser diode, which is depolarized by a depolarizer. Additional fiber lasers in accordance with embodiments of the present invention include a double clad active optical fiber having a pump power entry point for sending pump energy through the active optical fiber in a first direction, and a loop portion at a second end of the fiber for sending pump energy through the active optical fiber in a second direction which is opposite to the first direction. A system for coupling light into a fiber in accordance with embodiments of the present invention include a first fiber, a second double clad fiber, and a bulk optic component positioned between the first and second fibers. A mode stripper included within the second fiber allows for removal of high power light which is propagated through the outer clad rather than launched into the core of the second fiber.
摘要:
A coupler and method of coupling a signal beam between from a circular-core fiber to a rectangular-core cross section fiber includes providing an optical coupler having an optical core with a high-aspect ratio cross section at one end and a circular cross section at an opposite end to receive a signal beam having a circular cross section. The signal beam is propagated from the circular fiber to the rectangular-core cross section fiber in a narrow, fast-axis direction while maintaining the size and divergence of the signal beam as it propagates. The signal beam is expanded in size while producing a collimated beam from the circular cross section end to the rectangular-core cross section end in a wide, slow-axis direction.
摘要:
In one or more embodiments, an optical fiber coupler for coupling pump radiation into a rectangular optical fiber includes a fiber section and a pump fiber. The fiber section includes a core having a high aspect ratio cross-section and an interface section. The core is positioned in contact with first and second signal claddings to form reflective boundaries at fast-axis boundaries of the core. The pump fiber is side coupled to the fiber section via the interface section, and configured to couple the pump radiation into the fiber section.
摘要:
A laser amplifier includes a pump source and an optically active fiber having an input portion configured to receive a signal source and an output portion. The pump source is optically coupled to the optically active fiber. The laser amplifier also includes an output fiber optically coupled to the output portion of the optically active fiber. The output fiber includes a rare-earth element. The laser amplifier further includes a beam expansion section joined to the output fiber.
摘要:
A fiber laser is disclosed comprising a single mode or low-order-mode cladding pumped fiber laser oscillator or preamplifier, a cladding pumped fiber laser power amplifier to guide multiple transverse modes, wherein an output from the oscillator or preamplifier is applied through a mode mixing means to the power amplifier to provide that a laser signal of the cladding pumped fiber laser power amplifier is emitted from the fiber laser power amplifier in the multiple transverse modes.
摘要:
The invention relates to a fiber structure (700), which has one or more refractive index disturbances (750 , 760) outside a fiber core (710) for discriminating one or more high order modes in the fiber structure. The invention also relates to a method for discriminating one or more high order modes, an arrangement having the high order modes discriminating fiber structure, and a device having the high order mode discriminating fiber structure.