摘要:
An elongate waveguide for guiding light including a core having an elongate region of relatively low refractive index; a microstructured region around the core comprising elongate regions of relatively low refractive index interspersed with elongate regions of relatively high refractive index; and a boundary at the interface between the core and the microstructured region, the boundary including, in the transverse cross-section, a region of relatively high refractive index, which is connected to the microstructured region at a plurality of nodes, and at least one relatively enlarged region around the boundary, the enlarged region having a major dimension and a minor dimension, wherein the length of the major dimension divided by the length of the minor dimension is more than 3.0.
摘要:
A photonic crystal fiber comprising a bulk material having an arrangement of longitudinal holes, the fiber including a cladding region and a guiding core (280), the cladding region having an effective-refractive-index which varies across the fiber's cross section, wherein, in use, the effective-refractive-index variation causes light propagating in the fiber to have a different transverse profile from the profile that it would have if the cladding region were of a substantially uniform effective refractive index.
摘要:
A photonic crystal fiber including a plurality of longitudinal holes (220), in which at least some of the holes have a different cross-sectional area in a first region (200) of the fiber, that region having been heat-treated after fabrication of the fiber, from their cross-sectional area in a second region of the fiber (190), wherein the optical properties of the fiber in the heat-treated region (200) are altered by virtue of the change in cross-sectional area of holes (230) in that region (200).
摘要:
A method of manufacturing a microstructured fiber, includes: providing a preform having a plurality of elongate holes; mating at least one, but not all, of the holes with a connector to connect the hole(s) to an external pressure-controller; drawing the preform into the fiber while controlling gas pressure in the hole(s) connected to the pressure-controller.
摘要:
A photonic crystal fiber comprising a bulk material having an arrangement of longitudinal holes (130, 140) and a guiding core (135), wherein the fiber has at-most-two-fold rotational symmetry about a longitudinal axis and as a result of that lack of symmetry, the fiber is birefringent.
摘要:
In a method of producing a photonic crystal fibre, a preform (300) that includes holes is formed and the preform (300) is drawn into a fibre. The method includes the step of applying a pressure differential to certain of the holes to control changes in the fibre structure during the draw.
摘要:
A waveguide coupler comprises at least a first waveguide coupled at a coupling region to a second waveguide such that at least a part of radiation propagating along the first waveguide is coupled into the second waveguide. The second waveguide comprises a diffraction grating disposed at the coupling region to inhibit coupling of radiation from the first waveguide into the second waveguide at wavelengths characteristic of the diffraction grating.
摘要:
A waveguide coupler comprises at least a first waveguide coupled at a coupling region to a second waveguide such that at least a part of radiation propagating along the first waveguide is coupled into the second waveguide. The second waveguide comprises a diffraction grating disposed at the coupling region to inhibit coupling of radiation from the first waveguide into the second waveguide at wavelengths characteristic of the diffraction grating.
摘要:
An optical device comprises an optical fiber directional coupler having at least a first optical fiber optionally coupled at a coupling region to a second optical fiber such that light can propagate in the coupling region in at least two possible electromagnetic transmission modes; and means for transferring energy between the modes by a spatially periodic perturbation of at least a part of coupling region.
摘要:
A method of manufacturing a microstructured fibre, includes: providing a preform having a plurality of elongate holes; mating at least one, but not all, of the holes with a connector to connect the hole(s) to an external pressure-controller; drawing the preform into the fibre whilst controlling gas pressure in the hole(s) connected to the pressure-controller.