摘要:
Enhancement of the supercontinuum generation performance of a highly-nonlinear optical fiber (HNLF) is accomplished by incorporating at least one Bragg grating structure in the HNLF. The Bragg grating results in reflecting a core-guided signal into signal which also remains core-guided. The supercontinuum radiation generated by such an arrangement will exhibit a substantial peak in its energy at the grating resonance of the Bragg grating and a region of increased radiation in a narrow wavelength band on the long wavelength side of the peak. A number of such Bragg gratings may be formed so as to “tailor” the enhancements provided in the supercontinuum radiation. Various, well-known Bragg grating modifications (tuning, chirped, blazed, etc.) may also be used in the inventive structure to enhance the generated supercontinuum.
摘要:
An arrangement for generating beat notes with a relatively high signal-to-noise ratio (SNR) utilizes a pulsed laser source coupled into a section of post-processed highly-nonlinear optical fiber (HNLF) to generate a frequency comb having one or more regions of enhanced spectral power. A second laser signal source is overlapped with the frequency comb to form one or more “beat notes” at difference frequencies(y) between the second source and the continuum comb. By virtue of the post-processing, areas of spectral enhancement are formed along the comb, and are positioned to interact with the second laser signal to generate optical beat notes. The second laser signal may be from an external source (forming beat notes from a signal “outside” of the comb), or may be a frequency-multiplied version of the generated supercontinuum (forming beat notes from a signal “within” the comb).
摘要:
Enhancement of the supercontinuum generation performance of a highly-nonlinear optical fiber (HNLF) is accomplished by performing at least one post-processing treatment on the HNLF. Particularly, UV exposure of the HNLF will modify its dispersion and effective area characteristics so as to increase its supercontinuum bandwidth, without resorting to techniques such as tapering or introducing unwanted reflections into the HNLF. The UV exposure can be uniform, slowly varying or aperiodic along the length of the HNLF, where the radiation will modify the nonlinear properties of the HNLF. Various other methods of altering these properties may be used. The output from the HNLF can be monitored and used to control the post-processing operation in order to achieve a set of desired features in the enhanced supercontinuum spectrum.
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 matched pair of tilted gratings may be formed in a section of optical fiber (or waveguide) and used as a “tap” to measure the power of an optical signal passing through the fiber. By using a pair of highly-tilted gratings (e.g., tilted at an angle of 45° with respect to the optical axis) and orienting the gratings to be orthogonal with respect to one another (i.e., azimuthal orthogonality around the fiber axis), a pair of orthogonally polarized beams will be out-coupled from the propagating signal. Since the pair of beams are orthogonal, their sum can be made insensitive to variations in polarization of the optical signal propagating along the fiber.
摘要:
A system for remotely controlling client recording and storage behavior schedules the recording, storing, and deleting of multimedia content on a client system storage device. The invention accepts as input a prioritized list of program viewing preferences which is compared with a database of program guide objects that indicate when programs of interest are actually broadcast. A schedule of time versus available storage space is generated that is optimal for the viewer's explicit or derived preferred content. The viewer may request that certain content be captured, which results in the highest possible priority for those content. The invention provides objects called a capture requests that are sent by the service to client systems. Capture requests reflect local storage management decisions about how the client system storage is partitioned. Capture requests also allow the service to determine content to be recorded by the client system in the same manner that a viewer requests that certain content are recorded but are more powerful than what a viewer can request. Recording requests for a capture request can preempt viewer requests or be entered at the same or lower priority as a viewer request. Capture requests can adjust all aspects of a recording request and affect the capture request itself. Client system operational functionality are also manipulated by the service using capture requests.
摘要:
A system for remotely controlling client recording and storage behavior schedules the recording, storing, and deleting of multimedia content on a client system storage device. The invention accepts as input a prioritized list of program viewing preferences which is compared with a database of program guide objects that indicate when programs of interest are actually broadcast. A schedule of time versus available storage space is generated that is optimal for the viewer's explicit or derived preferred content. The viewer may request that certain content be captured, which results in the highest possible priority for those content. The invention provides objects called a capture requests that are sent by the service to client systems. Capture requests reflect local storage management decisions about how the client system storage is partitioned. Capture requests also allow the service to determine content to be recorded by the client system in the same manner that a viewer requests that certain content are recorded but are more powerful than what a viewer can request. Recording requests for a capture request can preempt viewer requests or be entered at the same or lower priority as a viewer request. Capture requests can adjust all aspects of a recording request and affect the capture request itself. Client system operational functionality are also manipulated by the service using capture requests.
摘要:
A method of nonlinear polarimetry for measuring higher order moments of the E field of an optical signal is provided. The method includes imposing a phase delay on a first polarization of a received optical signal with respect to a second polarization of the optical signal to produce an intermediate optical signal having a time varying polarization. A polarization of the intermediate optical signal is suppressed. The intermediate optical signal is detected with a plurality of photodetectors, with at least one photodetector configured to be responsive to a nonlinear optical process. Spectra of the photodetector outputs are calculated to determine higher order moments of the E field, and the moments are transformed to obtain the polarization measurement.
摘要:
A method, computer program product, and system are provided for defining a touch gesture on a touch sensing device. The method can include receiving a touch gesture at the touch sensing device, determining that the touch gesture is not associated with any operations, and providing an indication of one or more operations the touch sensing device can perform in response to the touch gesture. The method can also include receiving a selection of an operation, and associating the touch gesture with the selected operation.
摘要:
A method, computer program product, and system are provided for defining a touch gesture on a touch sensing device. The method can include receiving a touch gesture at the touch sensing device, determining that the touch gesture is not associated with any operations, and providing an indication of one or more operations the touch sensing device can perform in response to the touch gesture. The method can also include receiving a selection of an operation, and associating the touch gesture with the selected operation.