Patent application number | Description | Published |
20080225382 | Enhanced continuum generation in nonlinear bulk optic materials - In accordance with the present invention, a bulk optic material (for example, silica) is processed to form a spatially microstructured element, such as a photonic bandgap (PBG) structure. An ultra-short laser pulse source is used as an input signal that is applied to the bulk optic PBG structure to generate an enhanced continuum output. The PBG structure may comprise any type of one-, two- or three-dimensional grating structure, where the selected structure will dictate the type(s) of enhancement(s) that are present in the generated continuum—generally in the form of a broadened continuum and/or the inclusion of one or peaks in the continuum. The use of a relatively small-dimensioned bulk material allows for the continuum to be generated without the need for any type of optical confinement (waveguide). In one embodiment, the bulk PBG structure may be is subjected to one or more additional processes (such as UV exposure, electromagnetic field application, etc.) to modify the nonlinearity of the bulk optic material, in one case resulting in the reduction of the inherent chromatic dispersion and enhancement of the generated continuum. | 09-18-2008 |
20080232406 | Optical continuum source including light generation beyond wavelength edges of continuum - An optical continuum source is formed that is used to generate both a continuum and one or more light peaks outside the bandwidth of the continuum. In particular, one or more fiber Bragg gratings exhibiting a resonant wavelength less than the short wavelength edge (or greater than the long wavelength edge) of a predetermined continuum are inscribed into a section of highly nonlinear fiber (HNLF) and used to generate the additional light peaks. Gratings may also be formed for areas along the fiber where the continuum spectral power density is essentially “zero”. It has been discovered that the use of a Bragg grating generates phase matching with the propagating optical signal, thus resulting in the creation of the additional peaks. | 09-25-2008 |
20090080470 | Locally perturbed optical fibers for mode transformers - The specification describes optical devices and related methods wherein an input mode is converted by multiple LPG mode transformers to produce an output with multiple predetermined modes. | 03-26-2009 |
20090185771 | Tunable Dispersion Compensator with Minimum Differential Group Delay - 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 | 07-23-2009 |
20090263083 | APPARATUS FOR SIDE FIRE FIBER LASERS - A fiber laser having at least one pair of reflectors coupled to an optical fiber, the at least one pair of reflectors defining an optical cavity between the at least one pair of reflectors and being configured to reflect light within the optical cavity. At least one light pump is coupled to the optical fiber and configured to provide pump light into the optical cavity, and at least one medium is positioned within the optical cavity and configured to generate signal light from the pump light in the optical cavity. Further, at least one grating positioned within the optical cavity and configured to couple the signal light out of the optical cavity. | 10-22-2009 |
20100129029 | Optical fiber mode couplers - Described are optical devices and related methods wherein a multiple mode input in a Higher Order Mode (an HOM) optical fiber is converted by a complex mode transformer to produce a fundamental mode output in an optical medium with an E-field that is substantially different than that exiting the HOM optical fiber. The medium is preferably a Large Mode Area (LMA) optical fiber, or free space. The mode transformer may be a series of refractive index perturbations created either by photo-induced gratings or by gratings formed by physical deformations of the optical fiber. | 05-27-2010 |
20100148383 | Method of controlling longitudinal properties of optical fiber - A method of creating optical fiber to exhibit predetermined length-dependent characteristics (e.g., chromatic dispersion, polarization mode dispersion, cutoff wavelength, birefringence) includes the steps of: characterizing the fiber's selected characteristic(s) as a function of length; and performing a “treatment” which modifies the refractive index over the given length to adjust the defined parameter to fall within a defined tolerance window. These steps may be repeated one or more times until the measure of the parameter falls with the defined tolerance limits. The treatment process may include, for example, a low energy actinic radiation exposure, anneal, mechanical strain, DC voltage, plasma application, etc. Indeed, if the treatment process is repeated, a different technique may be used to adjust the refractive index (“different” processes include, for example, modifying the strength/time of a UV exposure, temperatures for annealing, etc.). | 06-17-2010 |
20110110619 | TUNABLE DISPERSION COMPENSATOR WITH MINIMUM DIFFERENTIAL GROUP DELAY - 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 | 05-12-2011 |
20120010842 | Self-Calibration Procedure For Optical Polarimeters - A procedure for self-calibration of an optical polarimeter has been developed that eliminates the need for “known” input signals to be used. The self-calibration data is then taken by moving a polarization controller between several random and unknown states of polarization (SOPs) and recording the detector output values (D | 01-12-2012 |
20140054451 | DBF FIBER LASER BEND SENSOR AND OPTICAL HETERODYNE MICROPHONE - Methods and systems using one or more distributed feedback (DFB) lasers for capturing changes in the lasing environment are disclosed. Specifically, a sensor for measuring a measurand, such as pressure or temperature, or changes in a measurand, includes a fiber with at least one core, at least one fiber laser cavity formed by a single fiber grating in the core, wherein the laser operates on at least two modes along at least part of its length. The DFB laser includes a section that is bent into a non-linear shape and at least one pump laser connected to the fiber laser cavity. When the DFB laser experiences a perturbation or measurand change that changes the spacing of the modes, a change in an RF beat note is generated. This beat note can then be measured and related to the measurand change. | 02-27-2014 |
20140079388 | Measuring In-Band Optical Signal-To-Noise Ratio (OSNR) - One measurement system comprises a polarimeter with a polarimeter detector bandwidth that partially overlaps with a signal bandwidth or completely overlaps with a signal bandwidth. The polarimeter measures a state of polarization (SOP) or a degree of polarization (DOP) of the signal in the presence of noise. The system further comprises a sampler that receives polarimeter signals from the polarimeter and samples those received signals at a specified sampling rate. The sampler outputs sampled data to a processor that calculates a mean DOP for the samples. Subsequently, the OSNR is determined from the calculated mean DOP. | 03-20-2014 |
20140112357 | Raman Distributed Feedback Fiber Laser and High Power Laser System Using the Same - A Raman distributed feedback (DFB) fiber laser is disclosed. It includes a pump source and a Raman gain fiber of a length smaller than 20 cm containing a distributed feedback (DFB) grating with a discrete phase structure located within no more than 10% off the center of the grating and wherein the Raman DFB fiber laser generates a laser signal with an optical spectrum, which has an optical bandwidth at half maximum optical intensity of less than 1 gigahertz (GHz) (wherein a maximum intensity frequency is different from the frequency of the pump laser). The Raman laser includes compensation for the nonlinear phase change due to Kerr effect and thermal effect resulting from absorption of the optical field, thus enhancing the conversion efficiency. | 04-24-2014 |
20140140693 | METHODS AND SYSTEMS FOR BULK DISPERSION MONITORING - A method and system for measuring chromatic dispersion, experienced by ASK/PSK modulated optical signals, are provided. Dispersion measurement is enabled either by encoding an additional overhead at lower baud rate or by monitoring signal SOP or RF spectrum of signal SOP. The bulk chromatic dispersion of the link is measured by analyzing the dispersion broadening of the overhead constellation or signal temporal diagram, or time-overlapped signal diagram, or overhead spectrum. This information is used to reduce the computation time required for electronic recovery of a highly dispersed signal. | 05-22-2014 |
20140218733 | IN-LINE ARRANGEMENT FOR MEASURING POLARIZATION EXTINCTION RATIO - An in-line polarization extinction ratio (PER) monitor that generates a value of an optical signal's PER from a single measurement, without requiring the optical transmission signal path of the system to be directly coupled into a separate measurement device. The polarization extinction ratio may be defined as: 10 log(P | 08-07-2014 |
20140232997 | INDEX MATCHED GRATING INSCRIPTION - The disclosed embodiments provide systems and methods for mitigating lensing and scattering as an optical fiber is being inscribed with a grating. The disclosed systems and methods mitigate the lensing phenomenon by surrounding an optical fiber with an index-matching material that is held in a vessel with a sealed phase mask. The sealed phase mask allows it to be in contact with a liquid index-matching material without having the liquid index-matching material seep into the grooves of the sealed phase mask. Thus, for some embodiments, the sealed phase mask may be immersed in a liquid index-matching material without adversely affecting the function of the phase mask. | 08-21-2014 |
20140233888 | INDEX MATCHED GRATING INSCRIPTION - The disclosed embodiments provide systems and methods for mitigating lensing and scattering as an optical fiber is being inscribed with a grating. The disclosed systems and methods mitigate the lensing phenomenon by surrounding an optical fiber with an index-matching material that is held in a vessel with an integrated interferometer (e.g., phase mask, etc.). The index-matching material has a refractive index that is sufficient to reduce intensity variations of the actinic radiation within the optical fiber. Some embodiments of the system include different vessels for holding the index-matching material, with the vessel having an interferometer integrated into the vessel. These vessels permit the optical fiber to be surrounded by the index-matching material while the gratings are written to the optical fiber. | 08-21-2014 |
20140233889 | INDEX MATCHED GRATING INSCRIPTION - The disclosed embodiments provide systems and methods for mitigating lensing and scattering as an optical fiber is being inscribed with a grating. The disclosed systems and methods mitigate the lensing phenomenon by surrounding an optical fiber with a liquid index-matching material that is held in a vessel. The disclosed systems also include a replenishment mechanism that replenishes the liquid index-matching material as the optical fiber is pulled through the vessel. | 08-21-2014 |
20140233890 | INDEX MATCHED GRATING INSCRIPTION - The disclosed embodiments provide systems and methods for mitigating lensing and scattering as an optical fiber is being inscribed with a grating. The disclosed systems and methods mitigate the lensing phenomenon by surrounding an optical fiber with an index-matching material that is held in a vessel with an integrated interferometer (e.g., phase mask, etc.). The index-matching material has a refractive index that is sufficient to reduce intensity variations of the actinic radiation within the optical fiber. Some embodiments of the system include different vessels for holding the index-matching material, with the vessel having an interferometer integrated into the vessel. These vessels permit the optical fiber to be surrounded by the index-matching material while the gratings are written to the optical fiber. | 08-21-2014 |
20140263985 | OPTICAL SENSOR HAVING FIDUCIARY MARKS DETECTED BY RAYLEIGH SCATTERED LIGHT - An optical fiber having at least one fiduciary mark is provided. The at least one fiduciary mark is located at one or more axial positions along the optical fiber. The at least one fiduciary mark is configured to produce at least one change in a Rayleigh backscattering signal in the optical fiber. The at least one change in a Rayleigh backscattering signal may be an abrupt change in the Rayleigh backscattering signal. The abrupt change in the Rayleigh backscattering signal occurs over a length of the optical fiber that is of the order of or less than a spatial resolution of an interrogation system employed to detect the Rayleigh backscattering signal. | 09-18-2014 |
20140268278 | Optical Polarimeter - A polarimeter is proposed that utilizes additional Stokes parameter measurements to determine both an average Stokes vector, as well as any rotation of the state of polarization around the Stokes vector. The optical polarimeter is configured to measure the state of polarization (SOP) under multiple, different conditions that yield both averaged Stokes vector and at least one other secondary (filtered) Stokes vector, the latter thus being determined from a subset of the conditions used to create the average Stokes vector. The secondary Stokes vector created from a filtered input will necessarily exhibit changes over time as a function of polarization transformations (based on filter-dependent changes), while the average Stokes vector will retain a constant value. Thus, a comparison of the average Stokes vector to the changing secondary Stokes vector allows for these polarization-dependent transformations to be recognized. | 09-18-2014 |
20140269789 | DISTRIBUTED FEEDBACK (DFB) BRILLOUIN FIBER LASERS - A Brillouin fiber laser uses a distributed feedback (DFB) fiber Bragg grating with a discrete π-phase shift, which is offset from the physical center of the grating as a resonator. Lasing is achieved by using the SBS gain in the DFB from narrow-linewidth laser pump radiation with an optical frequency that is higher than the central pass band of the grating by an amount nominally equal to the Stokes's frequency shift, ν | 09-18-2014 |
20140270643 | METHOD OF AND APPARARTUS FOR INSCRIPTION OF FIBER GRATINGS FROM MULTIPLE AZIMUTHAL ANGLES AND FIBER SO INSCRIBED - A method of, and apparatus for, inscribing a grating in an optical waveguide so as to reduce transverse inscription variations, are provided. The waveguide is exposed to multiple beams or interference patterns of actinic radiation from multiple azimuthal directions. The beams of actinic radiation are preferably split into a plurality of beams that have wave vectors with different longitudinal components, e.g., via gratings such as phase masks. The periods and phases of the interference patterns of the beams of actinic radiation are preferably matched. A control beam may be provided that does not hit the waveguide. A control loop optionally controls at least one of the position or orientation of at least one of the beams of actinic radiation. The gratings are, for example, Bragg gratings. | 09-18-2014 |
20140312014 | Compensation Of Fiber Lensing Effect During Grating Fabrication In Multicore Fiber - An arrangement and method that compensates for variation in grating strength associated with forming multiple gratings in multicore fiber is proposed where the writing efficiency of the beam(s) used to form the gratings is controlled to compensate for fiber lensing effects. In one case, a spacing between the multicore optical fiber and the beam source is controlled such that the writing efficiency (which decreases as a function of the space between the source and the fiber) compensates (at least in part) for the increased beam intensity attributed to the lensing effect of the fiber itself. The width of beam itself may also be controlled to modify the writing efficiency. | 10-23-2014 |