A laser apparatus operable to generate giant chirp pulses. The pulses have a centre frequency comprising an arrangement of components connected or connectable to form a closed ring cavity. The components comprise a first gain medium, an optical isolator, a length of single mode fibre, a mode locking device, an output coupler, and an optical filter. Each of the components are optical fibre based components.

An exemplary embodiment of the disclosure provides a double fiber optic mode adapter including: a fiber core having a variable core diameter; a fiber cladding having a variable cladding size; a first input interface corresponding to a first core diameter and a first cladding size; a second input interface corresponding to a second core diameter and a second cladding size; a thermally-tapered region wherein the variable core diameter of the fiber core transitions from the first core diameter to the second core diameter and the variable cladding size of the fiber cladding transitions from the first cladding size to a third cladding size; and an etched tapered region wherein the variable core diameter of the fiber core is constant and the variable cladding size of the fiber cladding transitions from the third cladding size to the second cladding size

A laser apparatus operable to generate giant chirp pulses. The pulses have a center frequency comprising an arrangement of components connected or connectable to form a closed ring cavity. The components comprise a first gain medium, an optical isolator, a length of single mode fiber, a mode locking device, an output coupler, and an optical filter. Each of the components are optical fiber based components.

A bundle structure is obtained by arranging optical fibers having equal diameters in a close-packed arrangement around the outer circumference of a center optical fiber. The optical fibers are signal light optical fibers that transmit signal lights. The optical fiber is a pump light optical fiber that transmits pump light. The number of optical fibers is equal to the number of cores in the multi-core fiber. The bundle structure and the multi-core fiber are connected to one another by adhering or fusing. The cores and the cores are optically connected, and the core and the cladding are optically connected. When connecting, the mode field diameter of the cores and the cores are substantially equivalent. In addition, the outer diameter (diameter of circumscribed circle including optical fibers) of the bundle structure is set so as not to be greater than the outer diameter of the multi-core fiber.

Beam combining optical systems include a fiber beam combiner having multiple inputs to which output fibers of laser diode sources are spliced. Cladding light stripping regions are situated at the splices and include exposed portions of fiber claddings that are at least partially encapsulated with an optical adhesive or a polymer. A beam combiner fiber that is optically downstream of a laser source has an exposed cladding secured to a thermally conductive support with a polymer or other material that is index matched to the exposed cladding. This construction permits attenuation of cladding light propagating toward a beam combiner from a splice.

According to one aspect, the invention relates to a device comprising an optical fiber having a high Brillouin threshold, said device including an optical fiber (101) suitable for propagating a high-power optical signal beam, means (11) for coupling a signal beam to an entrance end of the optical fiber (101) and a tubular structure (10) comprising at least one first tube (103) and at least one first adhesive material (102). According to the present description, at least one portion of the optical fiber is immobilized in the tubular structure (10) by means of the first adhesive material (102), which adheres both to the internal surface of the first tube (103) and to the external surface of the optical fiber (101). Furthermore, at room temperature and with no other external stresses on the device, the immobilized portion of the optical fiber (101) is maintained in a compressive state by the tubular structure, the compressive state being such that the relative deformation of the optical fiber is negative or zero in its portion immobilized in the tubular structure, the maximum value of the relative deformation of the immobilized portion of the optical fiber being higher in absolute value than 0.3%.

An apparatus includes a laser system that includes a first fiber having an output end and situated to propagate a first laser beam with a first beam parameter product (bpp) and a second fiber having an input end spliced to the output end of the first fiber at a fiber splice so as to receive the first laser beam and to form a second laser beam having a second bpp that is greater than the first bpp, wherein the output end of the first fiber and the input end of the second fiber are spliced at a tilt angle so as to increase the first bpp to the second bpp.

A laser utilizes a cavity design which allows the stable generation of high peak power pulses from mode-locked multi-mode fiber lasers, greatly extending the peak power limits of conventional mode-locked single-mode fiber lasers. Mode-locking may be induced by insertion of a saturable absorber into the cavity and by inserting one or more mode-filters to ensure the oscillation of the fundamental mode in the multi-mode fiber. The probability of damage of the absorber may be minimized by the insertion of an additional semiconductor optical power limiter into the cavity.

Embodiments of the present disclosure provide an optical repeater and an optical fiber communications system. An implementation solution of the optical repeater includes: a first input end of the optical repeater, a first output end of the optical repeater, a first erbium doped fiber, a first coupler, a second coupler, and a first pump light processing component, where the first input end of the optical repeater is connected to an input end of the first erbium doped fiber, an output end of the first erbium doped fiber is connected to an input end of the first coupler, a first output end of the first coupler is connected to a first input end of the second coupler, and an output end of the second coupler is connected to the first output end of the optical repeater.

A multi-core fiber optical amplifier includes: a multi-core excitation fiber configured to include a first core and a second core; and a clad excitation circuit configured to inject excitation light into a clad of the multi-core excitation fiber, wherein signal light input to one end of the first core is output from the other end of the first core, the signal light output from the other end of the first core is input to one end of the second core, and the signal light input to one end of the second core is output from the other end of the second core.