摘要:
An optical fiber includes a cladding with a material having a first refractive index and a pattern of regions formed therein. Each of the regions has a second refractive index lower than the first refractive index. The optical fiber further includes a core region and a core ring surrounding the core region and having an inner perimeter, an outer perimeter, and a thickness between the inner perimeter and the outer perimeter. The thickness is sized to reduce the number of ring surface modes supported by the core ring.
摘要:
An optical sensor includes an optical coupler. The optical sensor further includes a photonic bandgap fiber having a hollow core and an inner cladding generally surrounding the core. The photonic bandgap fiber is in optical communication with the optical coupler. Light signals counterpropagate through the photonic bandgap fiber and return to the optical coupler. The photonic bandgap fiber has a phase thermal constant S less than 8 parts-per-million per degree Celsius.
摘要:
A photonic-bandgap fiber includes a photonic crystal lattice with a material having a first refractive index and a pattern of regions formed therein. Each of the regions has a second refractive index lower than the first refractive index. The photonic-bandgap fiber further includes a core and a core ring surrounding the core and having an inner perimeter, an outer perimeter, and a thickness between the inner perimeter and the outer perimeter. The thickness is sized to reduce the number of ring surface modes supported by the core ring.
摘要:
An optical fiber includes a cladding with a material having a first refractive index and a pattern of regions formed therein. Each of the regions has a second refractive index lower than the first refractive index. The optical fiber further includes a core region and a core ring having an inner perimeter, an outer perimeter, and a thickness between the inner perimeter and the outer perimeter. The thickness is sized to reduce the number of ring surface modes supported by the core ring.
摘要:
An optical sensor includes a directional coupler comprising at least a first port, a second port, and a third port. The first port is in optical communication with the second port and with the third port such that a first optical signal received by the first port is split into a second optical signal that propagates to the second port and a third optical signal that propagates to the third port. The optical sensor further includes a photonic bandgap fiber having a hollow core and an inner cladding generally surrounding the core. The photonic bandgap fiber is in optical communication with the second port and with the third port. The second optical signal and the third optical signal counterpropagate through the photonic bandgap fiber and return to the third port and the second port, respectively. The photonic bandgap fiber has a phase thermal constant S less than 8 parts-per-million per degree Celsius.
摘要:
A photonic-bandgap fiber includes a photonic crystal lattice with a first material having a first refractive index and a pattern of a second material formed therein. The second material has a second refractive index lower than the first refractive index. The photonic crystal lattice has a plurality of first regions that support intensity lobes of the highest frequency bulk mode and has a plurality of second regions that do not support intensity lobes of the highest frequency bulk mode. The photonic-bandgap fiber further includes a central core formed in the photonic crystal lattice. The photonic-bandgap fiber further includes a core ring having an outer perimeter. The core ring surrounds the central core, wherein the outer perimeter of the core ring passes only through the second regions of the photonic crystal lattice.
摘要:
Coupling of core modes to surface modes in an air-core photonic-bandgap fiber (PBF) can cause large propagation losses. Computer simulations analyze the relationship between the geometry and the presence of surface modes in PBFs having a triangular hole pattern and identify ranges of core characteristic dimensions (e.g., radii) for which the fiber supports no surface modes (i.e., only core modes are present) over the entire wavelength range of the bandgap. In particular, for a hole spacing Λ and a hole radius ρ=0.47Λ, the core supports a single mode and supports no surface modes for core radii between about 0.68Λ and about 1.05Λ. The existence of surface modes can be predicted simply and expediently by studying either the bulk modes alone or the geometry of the fiber without requiring a full analysis of the defect modes.
摘要:
An optical fiber includes a cladding, a first core, and a second core. At least one of the first core and the second core is hollow and is substantially surrounded by the cladding. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core. The optical fiber includes a defect substantially surrounded by the cladding, the defect increasing a coupling coefficient between the first core and the second core.
摘要:
An optical coupler includes a first optical port, a second optical port, a third optical port, and a fourth optical port. The optical coupler further includes a photonic-bandgap fiber having a cladding, a first core, and a second core. The cladding includes a material with a first refractive index and regions within the cladding. The regions have a second refractive index lower than the first refractive index. The first core is substantially surrounded by the cladding. The first core is optically coupled to the first optical port and to the second optical port. The second core is substantially surrounded by the cladding. The second core is optically coupled to the third optical port and to the fourth optical port. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core such that the first core is optically coupled to the second core. The first core, the second core, or both the first core and the second core is hollow.
摘要:
An optical fiber includes a cladding, a first core, and a second core. At least one of the first core and the second core is hollow and is substantially surrounded by the cladding. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core. The optical fiber includes a defect substantially surrounded by the cladding, the defect increasing a coupling coefficient between the first core and the second core.