摘要:
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.
摘要:
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.
摘要:
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 λR (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 λR (10), which power is greater than an injection locking threshold of the laser diode.
摘要:
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 λR (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 λR (10), which power is greater than an injection locking threshold of the laser diode.
摘要:
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.
摘要:
An optical fibre including a waveguide and at least one stress applying region is described. The waveguide is defined by a numerical aperture, and the stress applying region is defined by a depressed refractive index. The optical fibre is configured such that the waveguide supports at least two polarised fundamental modes, two polarized first second-order modes, and two polarised second second-order modes. The waveguide includes comprises a gain medium. The stress applying region, the waveguide and the disposition of the gain medium are such as to provide preferential guidance to at least one of the modes at an operating wavelength.
摘要:
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.
摘要:
Apparatus for the industrial processing of a material by a fiber laser, which fiber laser emits optical radiation, the apparatus configured such that the optical radiation forms an optical power distribution on a surface of the material, including first and second optical powers which are located at respective first and second radii from a center of the optical power distribution and which are of substantially higher intensity than a third optical power which is located at a third radius from the center of the optical power distribution and which is smaller than the first and the second radii.
摘要:
Apparatus for combining laser radiation (1) 5 which apparatus comprises a seed laser (2), a splitter (3), a plurality of amplifier chains (4), a reference amplifier chain (7), detection means (5). demodulator means (6), and phase control means (12), wherein each of the amplifier chains (4) comprises at least one optical amplifier (11), optical radiation (17) emitted from the seed laser (2) is split into the plurality of amplifier chains (4) by the splitter (3). amplified by the plurality of amplifier chains (4), interfered, detected by the detection means (5), demodulated by the demodulator means (6), and a signal (27) indicative of path length imbalance (14) fed back to the phase control means (12), and wherein the apparatus is characterized in that the output power emitted by each amplifier chain (4) is at least 50 W, the bandwidth (8) of the seed laser (2) is at least 1 GHz, and the path length difference (14) between each amplifier chain (4) and the reference amplifier chain (7) is less than the coherence length (10) of the seed laser (2).
摘要:
Apparatus for combining laser radiation (1) 5 which apparatus comprises a seed laser (2), a splitter (3), a plurality of amplifier chains (4), a reference amplifier chain (7), detection means (5). demodulator means (6), and phase control means (12), wherein each of the amplifier chains (4) comprises at least one optical amplifier (11), optical radiation (17) emitted from the seed laser (2) is split into the plurality of amplifier chains (4) by the splitter (3). amplified by the plurality of amplifier chains (4), interfered, detected by the detection means (5), demodulated by the demodulator means (6), and a signal (27) indicative of path length imbalance (14) fed back to the phase control means (12), and wherein the apparatus is characterised in that the output power emitted by each amplifier chain (4) is at least 50 W, the bandwidth (8) of the seed laser (2) is at least 1 GHz, and the path length difference (14) between each amplifier chain (4) and the reference amplifier chain (7) is less than the coherence length (10) of the seed laser (2).