Abstract: Apparatus for providing optical radiation (15), which apparatus comprises an optical input (13), a coupler (2), a first semiconductor amplifier (3), a controller (4), a preamplifier (61), a power amplifier (62) and an output fibre (5), wherein: the optical input (13) is for receiving input optical radiation (14); the optical input (13) is connected in series to the coupler (2), the first semiconductor amplifier (3), the preamplifier (61), the power amplifier (62), and the output fibre (5); the apparatus being characterized in that: the first semiconductor amplifier (3) comprises a waveguide (6) having a low reflecting facet (8); the first semiconductor amplifier (3) is in a double pass configuration such that the low reflecting facet (8) is connected to both the optical input (13) and the preamplifier (61) via the coupler (2); and the controller (4) is configured to cause the waveguide (6) of the first semiconductor amplifier (3) to operate in saturation thereby enabling the first semiconductor amplifier (3)

Abstract: Apparatus for providing optical radiation (9), which apparatus comprises; a first seed source (1) for providing first seeding radiation (11); a second seed source (2) for providing second seeding radiation (12); a coupler (3) connected to the first seed source (1) and the second seed source (2) for coupling the first seeding radiation (11) and the second seeding radiation (12) together; and at least one amplifier (4) for amplifying the first seeding radiation (11) and the second seeding radiation (12).

Abstract: Apparatus for optical isolation, which apparatus comprises a laser (1), a beam delivery system (91), and an output port (92), wherein: the beam delivery system (91) comprises an optical isolator (8) and an optical fibre (2); the laser (1) is defined by a peak power (21); the laser (1) emits laser radiation (13) at a signal wavelength (19); the laser radiation (13) is coupled from the laser (1) to the output port (92) via the beam delivery system (91); and the optical fibre (2) comprises an optical waveguide (100) defined by a core (101), a cladding (102), a mode field area (104) at the signal wavelength (19), a length (86), and a Raman wavelength (25); and the apparatus being characterised in that: the Raman wavelength (25) is longer than the signal wavelength (19); the beam delivery system (91) attenuates the laser radiation (13) at the signal wavelength (19) such that the power of the laser radiation (13) emitted by the laser (1) is more than the power of the laser radiation (13) at the output port (92); th

Abstract: Apparatus for providing optical radiation (15), which apparatus comprises an optical input (13), a coupler (2), a first semiconductor amplifier (3), a controller (4), a preamplifier (61), a power amplifier (62) and an output fibre (5), wherein: the optical input (13) is for receiving input optical radiation (14); the optical input (13) is connected in series to the coupler (2), the first semiconductor amplifier (3), the preamplifier (61), the power amplifier (62), and the output fibre (5); the apparatus being characterized in that: the first semiconductor amplifier (3) comprises a waveguide (6) having a low reflecting facet (8); the first semiconductor amplifier (3) is in a double pass configuration such that the low reflecting facet (8) is connected to both the optical input (13) and the preamplifier (61) via the coupler (2); and the controller (4) is configured to cause the waveguide (6) of the first semiconductor amplifier (3) to operate in saturation thereby enabling the first semiconductor amplifier (3)

Abstract: Apparatus for optical isolation, which apparatus comprises a laser (1), a beam delivery system (91), and an output port (92), wherein: the beam delivery system (91) comprises an optical isolator (8) and an optical fibre (2); the laser (1) is defined by a peak power (21); the laser (1) emits laser radiation (13) at a signal wavelength (19); the laser radiation (13) is coupled from the laser (1) to the output port (92) via the beam delivery system (91); and the optical fibre (2) comprises an optical waveguide (100) defined by a core (101), a cladding (102), a mode field area (104) at the signal wavelength (19), a length (86), and a Raman wavelength (25); and the apparatus being characterised in that: the Raman wavelength (25) is longer than the signal wavelength (19); the beam delivery system (91) attenuates the laser radiation (13) at the signal wavelength (19) such that the power of the laser radiation (13) emitted by the laser (1) is more than the power of the laser radiation (13) at the output port (92); th

Abstract: An optical amplifier includes at least one pump source and an optical fiber cable which includes an amplifying optical fiber and a pump optical fiber that are defined by respective lengths. The amplifying optical fiber and the pump optical fiber are coated with a common coating along a portion of their respective lengths, and the fibers are in optical contact with each other along a coating length within the common coating. The common coating has a refractive index which is lower than a refractive index of a cladding material of the pump optical fiber. The fibers are made substantially from glass. The amplifying optical fiber includes a core and a cladding, and is doped with a rare earth dopant. The pump optical fiber is defined by a first end and a second end, the first end of the pump optical fiber being connected to the pump source.

Abstract: Laser apparatus (1) comprising a reference source (2), a reference fiber (3), and at least one laser diode (4), wherein the reference fiber (3) comprises a core (5) having a refractive index n1 and a first cladding (6) having a refractive index n2, the first cladding (6) is surrounded by a second cladding (7) having a refractive index n3, the refractive index n1 is greater than the refractive index n2, the refractive index n2 is greater than the refractive index n3, the laser diode (4) emits laser radiation (8) that is guided through the first cladding (6) of the reference fiber (3), the reference source (2) emits reference radiation (9) that has a predetermined wavelength ?R (10), the reference radiation (9) is guided through the core (5) of the reference fiber (3) to the laser diode (4), and the reference radiation (9) that is guided through the core (5) of the reference fiber (3) to the laser diode (4) has a power (11) at the predetermined wavelength ?R (10), which power is greater than an injection lockin

Abstract: An optical amplifier includes at least one pump source and an optical fibre cable which includes an amplifying optical fibre and a pump optical fibre that are defined by respective lengths. The amplifying optical fibre and the pump optical fibre are coated with a common coating along a portion of their respective lengths, and the fibres are in optical contact with each other along a coating length within the common coating. The common coating has a refractive index which is lower than a refractive index of a cladding material of the pump optical fibre. The fibres are made substantially from glass. The amplifying optical fibre includes a core and a cladding, and is doped with a rare earth dopant. The pump optical fibre is defined by a first end and a second end, the first end of the pump optical fibre being connected to the pump source.

Abstract: Laser apparatus (1) comprising a reference source (2), a reference fibre (3), and at least one laser diode (4), wherein the reference fibre (3) comprises a core (5) having a refractive index n1 and a first cladding (6) having a refractive index n2, the first cladding (6) is surrounded by a second cladding (7) having a refractive index n3, the refractive index n1 is greater than the refractive index n2, the refractive index n2 is greater than the refractive index n3, the laser diode (4) emits laser radiation (8) that is guided through the first cladding (6) of the reference fibre (3), the reference source (2) emits reference radiation (9) that has a predetermined wavelength ?R (10), the reference radiation (9) is guided through the core (5) of the reference fibre (3) to the laser diode (4), and the reference radiation (9) that is guided through the core (5) of the reference fibre (3) to the laser diode (4) has a power (11) at the predetermined wavelength ?R (10), which power is greater than an injection lockin

Abstract: An optical fiber arrangement has at least two optical fiber sections, each optical fiber section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fiber arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fiber. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fiber and a first multiplexer connected to the input fiber. Each amplifier is configured such that at least one of the amplifying optical fibers is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: Provided herein is an apparatus for optically isolating a light beam from a laser, comprising an optical isolator configured to isolate a light beam having a beam quality; a reference plane; an output connector disposed at the output of the optical isolator, wherein the output connector is configured with a common collimator interface to connect to a collimator which is capable of being mechanically referenced to the reference plane; a first lens arrangement disposed proximal to a distal end of the output connector, wherein the first lens arrangement is selected to provide an output light beam having a predetermined divergence. The laser can be selected from the group consisting of a fiber laser, a disk laser and a rod laser. Also provided herein are a system, a plurality of lasers, and a method of providing a light beam that has a consistent divergence and distance from a reference plane.

Abstract: In one embodiment, a photo-darkening resistant optical fibre includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the fibre includes a first cladding having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

Abstract: In one embodiment, a photo-darkening resistant optical fibre includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the fibre includes a first cladding having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

Abstract: In one embodiment, a photo-darkening resistant optical fiber includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the fiber includes a first cladding having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

Abstract: An optical fibre arrangement has at least two optical fibre sections, each optical fibre section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fibre arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fibre. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fibre and a first multiplexer connected to the input fibre. Each amplifier is configured such that at least one of the amplifying optical fibres is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: An optical fiber arrangement has at least two optical fiber sections, each optical fiber section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fiber arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fiber. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fiber and a first multiplexer connected to the input fiber. Each amplifier is configured such that at least one of the amplifying optical fibers is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: In one embodiment, a photo-darkening resistant optical fibre includes a waveguide having a numerical aperture less than 0.15. The waveguide includes a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the fibre includes a first cladding having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3. The core includes silica, a concentration of alumina of between approximately 0.3 to 0.8 mole percent, a concentration of phosphate of substantially 15 mole percent, a concentration of ytterbium substantially in the range 20000 to 45000 ppm. The pedestal can include silica, phosphate and germania. The core can have substantially zero thulium dopant.

Abstract: An optical fibre arrangement has at least two optical fibre sections, each optical fibre section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fibre arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fibre. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fibre and a first multiplexer connected to the input fibre. Each amplifier is configured such that at least one of the amplifying optical fibres is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: An optical fiber arrangement has at least two optical fiber sections, each optical fiber section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fiber arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fiber. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fiber and a first multiplexer connected to the input fiber. Each amplifier is configured such that at least one of the amplifying optical fibers is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: Apparatus for filtering optical radiation at an operating wavelength (19), which apparatus comprises a grating (1) written into a waveguide (2), and which grating (1) has a first end (3), a second end (91), a first bandwidth (24), a maximum re-flectivity (29), a first group delay variation (17) defined with respect to the first end (3), and a second group delay variation (18) defined with respect to the second end (91), wherein the first and second group delay variations (17), (18) are with respect to the first bandwidth (24), the maximum reflectivity (29) is greater than 50%, the first group delay variation (17) is between 0.1 ps and 100 ps, and the second group delay variation (18) is between 0.1 ps and 100 ps.