摘要:
An FBG element is configured to apply a phase shift to at least one of an input optical signal, a first pump light, and an idler signal between stages of a phase sensitive amplifier. The FBG element is apodized using a trapezoidal apodization function over the length of the first FBG element to enable tuning of the phase shift over a range of 2π radians.
摘要:
A post-assembly wavelength-tuning method for an optical filter provided along an optical fiber mounted under tension in a packaging assembly is provided. The packaging assembly includes at least one packaging component mechanically coupled to the optical fiber and optically accessible from outside of the packaging assembly. The method includes a step of measuring a post-assembly spectral response of the optical filter and determining therefrom a spectral deviation with respect to a target spectral response. The method also includes a step of forming one or more laser-welded zones on the packaging component so as to cause a permanent deformation thereof. The permanent deformation induces a modification in length of the optical fiber, thereby changing the post-assembly spectral response of the optical filter to compensate for the measured spectral deviation.
摘要:
Fiber optic position transducer that includes a magnetic or electromagnetic element, one or more segments of magnetostrictive material, Fiber Bragg Grating Sensors, a rod of material that is impenetrable to magnetic fields, optical fiber. One or more of the sensors is fixed upon a segment of magnetostrictive material, which is fixed to a rod, and may only be displaced longitudinally. The Fiber Bragg Grating Sensors have different wave lengths and are made of the same optical fiber. The magnetic or electromagnetic element included may be made of NdFeB (Neodymium Iron Boron) or metal alloys of TbDyFe (Terbium, Dysprosium and Iron), such as TX, Terphenol-D and others. It is applied to a control flow valve in an oil well, and it also refers to the calibration process of the position of the transducer.
摘要:
In a method and system for providing dispersion compensation in an optical system, there is coupled into the optical system at least one pathway into which there is connected a tunable chirped fiber Bragg grating, each such grating providing a respective tunable amount of dispersion. At least one respective DGD element is connected into the respective pathway for each such grating. The set of all such respective DGD elements in a given pathway introduces a bias differential group delay DGD(bias) having an absolute value that, for at least one tuning value of the grating, is substantially equal to differential group delay introduced by the grating.
摘要:
A mechanism for mapping an anatomical characteristic of a patient includes a treatment bed having a top surface. A fiber Bragg grating channel is disposed along at least a portion of the treatment bed near the top surface and includes a fiber optic waveguide defining a plurality of spaced-apart Bragg-type gratings. A multi-wavelength light source generates a beam that is in optical communication with the fiber Bragg grating channel. A detector, in optical communication with the fiber Bragg grating channel, detects reflections of light from at least one of the Bragg-type gratings. A computer is programmed to calculate at least one anatomical characteristic based on a characteristic of at least one of the reflection of light.
摘要:
A fiber including a fiber grating and at least one refractive index modifier interfacing the fiber grating, the at least one refractive index modifier selectively introducing a refractive-index change on the fiber grating.
摘要:
A tunable polarization dependent loss element is formed of a fiber including a highly tilted optical grating. The grating is formed at an angle of approximately 45° so as to preferentially scatter one polarization state out of the fiber core while allowing the remaining, orthogonal polarization to propagate unimpeded. By twisting the ends of the fiber grating structure, the orientation of the grating with respect to the fiber optical axis will be changed, modifying the amount of optical signal existing in each polarization state. In one embodiment, both ends may be rotated in the same direction through the same angular displacement, resulting in merely rotating the principle states of polarization in the fiber. Alternatively, the ends of the grating may be rotated (twisted) in opposite directions so as to couple all of the light signal into a single polarization state, reducing the amount of polarization dependent loss to essentially zero. Therefore, by controlling the twist imparted to the grating, the amount of exhibited polarization dependent loss can also be controlled.
摘要:
A tunable dispersion compensator for the compensation of the chromatic dispersion experienced by a single-channel or multi-channel light signal. The compensator includes a plurality of optical structures such as chirped Bragg gratings or combinations thereof, each having a characteristic dispersion profile. An optical coupling arrangement successively propagates the light signal in each of these structures, so that it accumulates the dispersion compensation effect of each. A tuning device jointly tunes the dispersion profile of each optical structure by applying a same tuning force thereto, preferably a temperature gradient.
摘要:
The present invention provides an Internet search engine system and method that improves searching for documents or pages by processing the characteristics of a pool of data through a neural network governed by a set of rules and fuzzy logic applications. The rules and applications may be implemented at the input (or low) level or the computational/output (or high) level. Search terms and personal and situational data may activate various rule sets, and learning from human and machine feedback adjust and recombine the rule sets to improve accuracy for future searches as well as reduce computation time.
摘要:
A tunable dispersion compensator for the compensation of the chromatic dispersion experienced by a single-channel or multi-channel light signal. The compensator includes a plurality of optical structures such as chirped Bragg gratings or combinations thereof, each having a characteristic dispersion profile. An optical coupling arrangement successively propagates the light signal in each of these structures, so that it accumulates the dispersion compensation effect of each. A tuning device jointly tunes the dispersion profile of each optical structure by applying a same tuning force thereto, preferably a temperature gradient.