Abstract: An optical imaging apparatus based on optical frequency domain measurement (OFDM) collects scatter data at multiple locations within or on the DUT as a function of time. A light source launches light into a device under test (DUT) which scatters light at one or more locations along the DUT. A light detector detects a portion of light scattered at each of multiple locations along the DUT. Data is determined using OFDM data processing that corresponds to an amount of light collected at each of the multiple locations along the DUT as a function of time. The data is stored for each of the multiple locations along the DUT. User information is provided that indicates an amount of light scattered at each of the multiple locations along the DUT based on the stored time domain data. The OFDM processing permits fine time resolution (e.g., 0.1 picoseconds) that allows small optical delay distances (e.g., 30 microns) to be resolved and allows for accurate detection of small amounts of scatter (e.g.

Abstract: A method of distributed acoustic sensing (DAS) whereby the derivative or rate of change of a signal backscatted from a fiber is measured. The change, or derivative of the phase measured in this way has a much smaller amplitude than the signal itself if the difference between the two times at which the signal is measured is much less than the period of the signal being measured, resulting in lower sensitivity. Frequency shifts can be applied to temporally displaced return signals to compare the rate of change, for example by employing an output interferometer arranged to modulate the signal in each arm by a different frequency shift.

Abstract: A method of evaluating integrity of a fiber comprises transmitting a measurement light beam through the optical fiber and measuring an intensity of a combined reflection of the measurement light beam. The combined reflection includes a proximal end reflection component and a distal end reflection component. The method further comprises separating the proximal end reflection component from the combined reflection to obtain a calibrated intensity measurement; and analyzing the calibrated intensity measurement to determine the integrity of the optical fiber.

Abstract: A method for compensating for both material or chromatic dispersion and modal dispersion effects in a multimode fiber transmission system is provided. The method includes, but is not limited to measuring a fiber-coupled spatial spectral distribution of the multimode fiber laser transmitter connected with a reference multimode fiber optical cable and determining the amount of chromatic dispersion and modal dispersion present in the reference multimode fiber optic cable. The method also includes, but is not limited to, designing an improved multimode fiber optic cable which compensates for at least a portion of the chromatic dispersion and modal dispersion present in the reference multimode fiber optic cable resulting from the transmitter's fiber-coupled spatial spectral distribution.

Abstract: A measurement end of an optical fiber is passed through a through hole of a holder. While the optical fiber is being rotated by using the through hole as a guide, output light from the measurement end is received by light receiving means. Coordinates of at least three points on a locus circle of the output light are measured to calculate a size of the locus circle. On the basis of the calculated size, the exit angle of the optical fiber is measured. The through hole of the holder has a small-diameter portion on a front side and a large-diameter portion on a rear side. An inside diameter of the small-diameter portion is 0.1 ?m to 1.0 ?m larger than a diameter of a bare fiber, and an inside diameter of the large-diameter portion is larger than a diameter of a sheathed fiber.

Abstract: An interferometric measurement system includes a spun optical fiber including multiple optical waveguides configured in the fiber. Interferometric detection circuitry detects measurement interferometric pattern data associated with each of the multiple optical waveguides when the optical fiber is placed into a bend. Data processing circuitry determines compensation parameters that compensate for variations between an optimal configuration of the multiple optical waveguides in the fiber and an actual configuration of multiple optical waveguides in the fiber. The compensation parameters are stored in memory for compensating subsequently-obtained measurement interferometric pattern data for the fiber.

Abstract: This disclosure concerns a cleaning and inspection system for fiber optics that is rapid, reliable and useful for various types of fiber optics. In an embodiment, the system includes a wide field of view (FOV) camera to image the ferrule and rapidly locate the fiber ends and a narrow FOV camera to provide detailed inspection of fiber ends. A cleaning module with a cleaning tip and a cleaning media that is drawn through the tip is used to clean the fiber ends. Images captured by the dual cameras are automatically enhanced and analyzed to determine the effectiveness of the cleaning process and to identify the types and quantity of defects present. In another embodiment, a single higher resolution camera is provided with a lens that can image an entire fiber array and yet enable defects to be detected by analysis of sub-images of each fiber in the fiber array.

Abstract: According to one embodiment, an optical sensing system may include a gated optical amplifier, one or more triggering devices, and an optical coupler. The gated optical amplifier can receive a pulse signal and transform the pulse signal into an amplified pulse signal having an amplified peak portion. The triggering devices can control the gated optical amplifier such that the gated optical amplifier is in the lossy state while the baseline portion of the pulse signal is transformed and the gated optical amplifier is in the gain state while the peak portion of the pulse signal is transformed. The amplified pulse signal can be transmitted to the sensing optical fiber and a sensed optical signal can be received, when the sensing optical fiber is connected to the optical coupler. Optionally, a second pulse signal and the sensed optical signal can be combined and detected with a coherent balanced detection technique.

Abstract: A method may include injecting a test signal having a first optical launch power into a device under test via an optical splitter. The optical splitter includes at least two upstream ports and a downstream port and the test signal is injected in a first upstream port of the optical splitter. The device under test is coupled to the downstream port. Return loss associated with the device under test is measured at a second upstream input of the optical splitter. The RL measurement in stored a database. The injecting, measuring, and storing are repeated for a number of different optical launch powers.

Abstract: There is disclosed a distributed optical fiber sensing system in which the sensor fiber comprises at least first and second waveguides used for separate sensing operations. The sensor fiber may be, for example, a double clad fiber having a monomode core and a multimode inner cladding.

Abstract: Bending of an optical fiber where a heat may be generated by a high output power can be detected without using a dedicated light source. An optical communication module that outputs a continuous wave light generated by at least one light source to an optical fiber transmission line, includes: (1) a loss measurement unit that measures a loss of an amplified spontaneous emission generated by allowing the continuous wave light output from the light source to create stimulated Raman scattering in the optical fiber transmission line; (2) a fiber abnormality analyzer that detects the abnormal state of the optical fiber transmission line on the basis of loss information on the ASE measured by the loss measurement unit; and (3) a light source controller that controls a supply state of the continuous wave light from the light source on the basis of the detection of the fiber abnormality analyzer.

Abstract: An optical signal inspection device includes a housing, a diagnostic unit, an optical specimen holder, a light-shielding module, and a guiding unit. A receiving space is defined internally of the housing. The housing has an optical fiber holding area formed thereon. The optical specimen holder has an upper jaw member and a lower jaw member. The light shielding module has a main body and two lateral shielding members disposed thereon. Two side portions of the lower jaw member are formed matchingly to the lateral shielding members. The guiding unit is secured to the upper or lower jaw member. When the upper and lower jaw members are used to clamp the optical fiber for inspection, interference due to ambient lighting can be prevented by the light shielding module. Thus, quick and accurate inspection results can be obtained by the user.

Abstract: A system and method for determining optical distribution network connectivity. In one embodiment, the system includes: (1) a transceiver configured to monitor at least one parameter and (2) a fiber bending device configured to introduce a bend into a particular fiber, the parameter exhibiting a corresponding attenuation when the bend is introduced and indicating a connectivity of the particular fiber.

Abstract: An optical fiber network test method of an optical frequency domain reflectometer, which is to use the optical testing apparatus and method of the prevent invention to combine the characters of filtering, reflecting and transmission of light of the wave reflecting unit, applying on any optical fiber test or point-to-point or point-to-multipoint optical fiber network. Thus, the optical fiber testing apprartus and method is constructed, and the goals of achieving the optical fiber network test method of the optical frequency domain reflectometer or confirming simultaneously the position of the barrier router and the barrier optical fiber connection point/end point/start point can be accomplished.

Abstract: An optical time domain reflectometry system is described which provides low-power, low weight, optical fiber system integrity measurements in an in-situ optical fiber system. The system can be integrated within the transmitter component to allow both data transmission and OTDR measurement functions. A method of providing several different modes of OTDR measurement through external control is also disclosed.

Abstract: A method for accurately measuring the cutoff wavelength of a high order mode of an optical fiber includes a first step of measuring power spectrum P1(?) of light output from a light source; a second step of measuring power spectrum P2(?) of light emitted from one end of a test fiber when light output from the light source is made incident on the other end of the test fiber placed in a form (preferably spiral) allowing the curvature to vary in the longitudinal direction thereof; a third step of obtaining difference spectrum P(?) representing the difference between the power spectrum P2(?) and the power spectrum P1(?); and a fourth step of obtaining the cutoff wavelength of a high order mode of the test fiber on the basis of the difference spectrum P(?).

Abstract: A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size<2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.

Abstract: Embodiments of the invention include systems and methods for measuring or otherwise calculating polarization mode dispersion (PMD) of an optical fiber, or other device, by comparing the optical signal through the PMD element with the optical signal obtained directly from the transmitter, and calculating the PMD from the discrepancy between the two. Any distortions on the transmitter signal are effectively calibrated out, increasing measurement accuracy over conventional approaches.

Abstract: An exemplary optical transmission system comprises an optical subassembly (OSA) coupled to an optical receiver via an optical fiber. The OSA comprises a laser diode configured to transmit optical signals across the optical fiber, and the OSA further comprises an avalanche photodiode (APD) configured to receive optical return signals from the optical fiber. The system further comprises a crosstalk canceller configured to estimate an amount of electrical crosstalk affecting measurements of the return signals in order to cancel such crosstalk from measurements of subsequent optical signals received by the APD.

Abstract: In a method and a corresponding apparatus for performing chaotic optical time domain reflectometer, the chaotic laser signal, generated by the chaotic laser transmitter, is split into probe signal I and reference signal II by a fiber coupler. Through an optical circulator, the probe signal I is launched into the test fiber and the echo light is converted into electrical signal by a photodetector and digitalized by an A/D converter. The reference signal II is converted into electrical signal by a photodetector and digitalized by another A/D converter. Two digital signals received from two A/D converters are correlated in a signal processing device to locate the exact position of faults in fibers. The result output is then displayed on a display device. This invention was developed to overcome the tradeoff problem between resolution and dynamic range of the pulse-based OTDR.

Abstract: A test instrument comprises plural first optical signal sources at a first wavelength and a distributor coupled to the plural first optical signal sources to supply the signals produced to a multi-fiber test port. Additional second wavelength signal sources may be provided, and a second test instrument for use at a second end of the link under test may be provided, to effect testing of the optical link.

Abstract: The invention at hand concerns a method and a system for transmitting data in an optical transmission system. A measuring signal is generated having a wavelength which differs from the wavelengths of a data signal that includes the data to be transmitted. The measuring signal is coupled in the optical transmission system, reflected after passing through the transmission path and decoupled again. The coupled measuring signal is compared with the decoupled reflected measuring signal. By taking into account the comparison results, a compensation of the change of the data signal resulting from the dispersion in the fiber is performed in such a way that the data included in the data signal can be used.

Abstract: Problems of excessive fading in systems for monitoring single-mode optical fiber for disturbances are addressed by launching into the fiber polarized light having at least two different predetermined launch states of polarization whose respective Stokes vectors are linearly-independent of each other; downstream from the first location, receiving the light from the fiber; analyzing the received light using polarization state analyzer having at least two different analyzer states of polarization that are characterized by respective Stokes vectors that are linearly-independent and detecting the analyzed light to provide corresponding detection signals; deriving from the detection signals measures of changes in polarization transformation properties of the fiber between different times that are invariant under a non-reflective unitary transformation on either the launch states or the detection states; and, on the basis of predefined acceptable physical disturbance criteria determining whether or not the measures

Abstract: Problems of excessive fading in systems for monitoring single-mode optical fiber for physical disturbances are addressed by launching into the fiber polarized light having at least two different predetermined launch states of polarization whose respective Stokes vectors are linearly-independent of each other; downstream from the first location, receiving the light from the fiber; analyzing the received light using polarization state analyzer means having at least two different analyzer states of polarization that are characterized by respective Stokes vectors that are linearly-independent of each other and detecting the analyzed light to provide corresponding detection signals; deriving from the detection signals measures of changes in polarization transformation properties of the fiber between different times that are substantially independent of said launch states and said detection states; and, on the basis of predefined acceptable physical disturbance criteria determining whether or not the measures are i

Abstract: The inventive configurable chiral fiber sensor with a tip-positioned sensing element, is readily configurable for use in a variety of applications (such as applications involving pressure, temperature, and even axial twist sensing), and is particularly suitable for applications requiring highly precise and accurate sensor readings within corresponding predefined limited sensing ranges. Advantageously, the inventive configurable chiral fiber sensor with a tip-positioned sensing element, is operable to utilize a wide variety of light sources, photodetectors, and related devices for sensor interrogation.

Abstract: The inventive configurable chiral fiber sensor is readily configurable for use in a variety of applications (such as applications involving pressure and/or temperature sensing), and which is particularly suitable for applications in which the sensing of a presence or absence of the target sensed event (e.g., specific minimum pressure or minimum temperature) is required. Advantageously, the inventive configurable chiral fiber sensor utilizes light sources, photodetectors, and related devices for sensor interrogation.

Abstract: Some embodiments of a distributed Brillouin optical fiber sensing system employs a sensing optical fiber that supports two or more (i.e., few) guided modes. Pump light supported by one of the guided modes is used to form a dynamic Brillouin grating (DBG). Probe light supported by at least one of the other guided modes interacts with the DBG to form reflected probe light that is received and analyzed to determine a Brillouin frequency shift, a phase matching wavelength between probe and pump light, a reflection location, which in turn allows for making a measurement of at least one condition along the sensing optical fiber. Supporting the pump and probe light in different guided modes results in the optical fiber sensing system being able to simultaneously measure temperature and strain and having a higher spatial resolution than sensing systems where the pump light and probe light share a common guided mode.

Abstract: A system may include a first measurement device configured to be coupled to a first node in an optical path being measured. The first measurement device may be configured to generate a signal at an initiating device; identify an unused channel in an optical path, wherein the optical path includes at least two spans; and transmit the signal on the unused channel. A second test device may be configured to be coupled to a last node in the optical path being measured. The second measurement device may be configured to: receive the signal at a destination device; compensate the signal for chromatic dispersion (CD) and/or polarization mode dispersion (PMD) effects; and determine CD and/or PMD measurements associated with the optical path being measured based on the compensation.

Abstract: A distributed Brillouin optical fiber sensing system employs a sensing optical fiber that supports two or more (i.e., few) guided modes. Pump light supported by one of the guided modes is used to form a dynamic Brillouin grating (DBG). Probe light supported by at least one of the other guided modes interacts with the DBG to form reflected probe light that is received and analyzed to determine a Brillouin frequency shift and a reflection location, which in turn allows for making a measurement of at least one condition along the sensing optical fiber. Supporting the pump and probe light in different guided modes results in the optical fiber sensing system having a higher spatial resolution than sensing systems where the pump light and probe light share a common guided mode.

Abstract: The present invention relates to a device and method for measuring the differential delay in a computer system having a disaster recovery secondary site. The device includes a transmitter for use at a primary site, the transmitter having a first laser and a second laser. The first laser is optically connected to an end of the transmission path and the second laser is optically connected to an end of the receive path. A receiver is located at the secondary site. The receiver has a first optical receiver optically connected to an end of the transmission path and a second optical receiver optically connected to an end of the receive path. The receiver includes a microprocessor to count the number of cycles between the receipt of light pulses simultaneously emitted from the first and second lasers. From this cycle count, the differential delay between the transmission and receive path is calculated.

Abstract: Subject matter disclosed herein relates to measuring optical fibers, and, in particular, to measuring spontaneous emission produced in an optical fiber.

Abstract: A system for monitoring a plurality of components distributed in different space locations, includes: at least one optical fiber path; an optical radiation source adapted to inject optical radiation into the at least one optical fiber path; at least one first and at least one second optical branches branching from the at least one optical fiber path and adapted to spill respective portions of the optical radiation, the first and second optical branches being adapted to be operatively associated with a respective component to be monitored.

Abstract: A new metric applicable to the characterization and design of multimode fiber (MMF) is described. The metric is derived from a Differential Mode Delay (DMD) measurement and when used in combination with industry-standard metrics such as Effective Modal Bandwidth (EMB) and DMD, yields a more accurate prediction of MMF channel link performance as measured by Bit Error Rate (BER) testing. The metric can also be used in the design of MMF for improved bandwidth performance. When implemented as a test algorithm in production, it can be used to select, sort, or verify fiber performance. This process can yield a multimode fiber design with a greater performance margin for a given length, and/or a greater length for a given performance margin.

Abstract: A conically tapered optical fiber with a small half-angle ? (e.g., less than 10?2) has been found able to support whispering gallery mode (WGM) resonances and can therefore be used to form a high-Q cavity. This finding has led to the ability to measure angstrom-level variations in the radius of an optical fiber by viewing the resonance spectrum at various locations where a sensor contacts an optical fiber being measured. An evaluation process is proposed where a microfiber sensor is brought into contact with a target fiber and the created WGM resonance is measured so that location radius variation can be characterized. The sensor is then removed from the target fiber and re-positioned to contact the fiber to another location to repeat the evaluation.

Abstract: In order to simplify and expedite identification of fibers (DF1/1, . . . , DF2/4) in multi-fiber cables (DF1, DF2), a method of identifying each of a plurality of fibers includes the steps of launching light into each of the fibers using an OTDR and applying a unique signature to each resulting OTDR trace by means of an event feature box comprising signature-applying means (EB) connected to a distal end of the fibers. The resulting plurality of OTDR traces have different signatures, enabling identification of each of the fibers by detecting its signature in the corresponding OTDR trace.

Abstract: Opto-electronic signal processing systems, apparatus and methods to extract a measured parameter from one or more interrogated optical sensors are disclosed. The apparatus includes an integrated laser module, an electronic control and processing unit, an optical coupling element, and one or more light receivers. Light is reflected back from the optical sensor through the optical coupling element to the light receiver(s). The electronic control and processing unit controls the wavelength of the integrated laser module using thermal control and, at the same time, detecting the wavelength of the integrated laser module using a wavelength selective element of the integrated laser module. According to the method, a wavelength sweep from the integrated laser module wavelength is swept, simultaneously measured and stored in memory of the electronic control and processing unit.

Abstract: A method for determining optical properties of an optical fiber including providing optical fibers having varying values of an optical property, measuring values of the optical property of the fibers, selecting one of the fibers as a reference fiber, determining the relative backscatter coefficient of the fibers compared to the reference optical fiber, correlating data obtained in step ii) with data obtained in step iv) to obtain a calibration curve showing a correlation between the Rrel and the values of the optical property of the optical fibers, measuring the Rrel of another optical fiber compared to the reference fiber, and determining a value of the optical property of the another optical fiber based on the calibration curve obtained in step v).

Abstract: An analytical device including an optically opaque cladding, a sequencing layer including a substrate disposed below the cladding, and a waveguide assembly for receiving optical illumination and introducing illumination into the device. The illumination may be received from a top, a side edge, and a bottom of the device. The waveguide assembly may include a nanoscale aperture disposed in the substrate and extending through the cladding. The aperture defines a reaction cell for receiving a set of reactants. In various aspects, the device includes a sensor element and the illumination pathway is through the sensor element. Waveguides and illumination devices, such as plasmonic illumination devices, are also disclosed. Methods for forming and operating the devices are also disclosed.

Abstract: An apparatus for illuminating optical fibers, said apparatus includes a housing having a face; fiber ports disposed on said face, each of said fiber ports being configured to engage a connector on an optical fiber; port lamps, each being disposed to provide light through a corresponding one of said fiber ports; and a control system configured to cause said port lamps to provide light according to corresponding port signatures, said port signatures being distinct from each other.

Abstract: Embodiments of the present disclosure disclose an OTDR test signal modulation circuit, including a laser diode drive, a laser diode, a current adjusting unit, and an OTDR control unit. The laser diode drive is connected to the laser diode and is configured to drive, according to an input data signal, the laser diode to transmit data light. The current adjusting unit is connected to the laser diode and the OTDR control unit and is configured to adjust a current flowing through the laser diode according to an OTDR test signal provided by the OTDR control unit, so as to modulate the OTDR test signal to the data light transmitted by the laser diode. Moreover, the embodiments of the present disclosure also disclose a passive optical network system and apparatus.

Abstract: The disclosure provides a method and a system for detecting a fiber fault in a Passive Optical Network (PON). The system comprises an optical path detection device, a Wavelength Division Multiplexing (WDM) coupler, a wavelength selection coupler, a branch fiber selector and a wavelength selection router. The detection system is attached to an original PON system, without influencing the operation of the original system while performing the detection. With the disclosure, the problem of being unable to determine whether there is a fault in a branch fiber due to the loss of an optical path detection reflection signal is solved, the branch fiber with a fault can be quickly located and fixed, thus the operational and maintenance costs of an operator are reduced.

Abstract: A system for monitoring an optical cable includes a cable having monitor fibers solely for monitoring cable status. The monitor fibers may be fibers selected from optical fibers having a higher mechanical sensitivity to mechanical stresses than other fibers in the cable, which may attenuate earlier than the other fibers in the event of cable degradation. The monitor fibers may be in communication with a transmitter and receiver, for transmitting and receiving a monitor signal. The receiver may be in communication with an alarm, the alarm being operative to send an alert signal when an increased attenuation is detected from the monitor signal, the increased attenuation being indicative of the status of the optical cable.

Abstract: A method for detecting faulty laying down of an optical cable exhibiting a measured cut-off wavelength includes providing an optical cable for transmitting optical signals including at least one single-mode optical fibre having an attenuation equal to or larger than a first threshold value as measured when wound for one turn around a bending radius equal to or smaller than 5 mm at at least one predetermined test wavelength, the test wavelength being smaller than the measured cut-off wavelength, and an attenuation smaller than a second threshold value as measured when wound for one turn around a bending radius equal to at least a minimum bending radius at an operative wavelength equal to or larger than the measured cut-off wavelength; laying the optical cable; and measuring the attenuation in the at least one optical fibre at the predetermined test wavelength.

Abstract: A system for determining spatial coherence, temporal coherence or both of an optical signal includes a fiber bundle containing optical fibers. Optical fiber inputs are arranged in proximate groups having the same number of fibers. The groups can each receive a portion of the optical signal. Each fiber in the group has a gross length that differs from the other fibers, but each group has the same set of different gross lengths. The fibers are joined to a lens which spreads the optical signal and causes interference between portions of the signal. This interference is detected at a detector. A computer joined to the detector can measure spatial and temporal coherence from the interference. Other embodiments feature multiple detectors and reflection along the bundle.

Abstract: A system and method for locating and identifying unknown samples. A targeting mode may be utilized to scan regions of interest for potential unknown materials. This targeting mode may interrogate regions of interest using SWIR and/or fluorescence spectroscopic and imaging techniques. Unknown samples detected in regions of interest may be further interrogated using a combination of Raman and LIBS techniques to identify the unknown samples. Structured illumination may be used to interrogate an unknown sample. Data sets generated during interrogation may be compared to a reference database comprising a plurality of reference data sets, each associated with a known material. The system and method may be used to identify a variety of materials including: biological, chemical, explosive, hazardous, concealment, and non-hazardous materials.

Abstract: A method of classifying a graded-index multimode optical fiber includes taking a series of individual measurements at a single wavelength, and using the measurements to characterize the departure of the multimode optical fiber's actual index profile from the corresponding nominal index profile. The measurements, coupled with intermodal dispersion or EMB measurement, may be used to predict the approximate transmission properties of the optical fiber at wavelengths other than the measurement wavelength. It is desirable for a graded-index multimode optical fiber to possess, at a wavelength of 850 nanometers, a radial offset bandwidth of at least 6000 MHz·km for all radial offsets between 0 and about 70 percent of the radius of the optical fiber's core.

Abstract: The output modal content of optical fibers that contain more than one spatial mode may be analyzed and quantified by measuring interference between co-propagating modes in the optical fiber. By spatially resolving the interference, an image of the spatial beat pattern between two modes may be constructed, thereby providing information about the modes supported by the optical fiber. Measurements of the phase front exiting the optical fiber under test are advantageously performed in the far field.

Abstract: A method of assessing the power penalty at a given bit error rate of a multimode fiber including measuring a set of elementary fiber responses corresponding to different offset launches of light over the core radius into the multimode fiber, generating a global fiber response by applying, to the set of elementary fiber responses, a set of weighting coefficients and delays depending on the different offset launches of the elementary fiber responses, and computing a parameter representative of a fiber power penalty from the global fiber response, wherein the set of weighting coefficients includes several subsets of weighting coefficients time delayed relative to one another, wherein at least one relative time delay is not set to zero, and wherein weighting coefficients of each subset depend on the different offset launches of the elementary fiber responses.

Abstract: An optical fiber curvature measuring method comprising rotatably holding an end of the optical fiber, irradiating two points at a prescribed distance from each other on a side surface of the fiber with a pair of parallel light beams orthogonal to an axial direction, measuring representative positions of scattered and reflected light beams scattered by the side surface as coordinate positions on an axis parallel to the optical fiber axis, calculating a difference between the two coordinate positions, rotating the fiber by a prescribed angle, repeating the calculation of the difference a plurality of times, calculating a positive representative value for amplitude SA from the difference obtained at each angle, calculating curvature from the amplitude SA as a first curvature of a first optical fiber longitudinal position, changing positions of the beams irradiating the fiber in the longitudinal direction, and calculating first to m-th curvatures by repeating this process.

Abstract: Disclosed are systems and methods for characterizing a nonlinear propagation environment by numerically propagating a measured output waveform resulting from a known input waveform. The numerical propagation reconstructs the input waveform, and in the process, the nonlinear environment is characterized. In certain embodiments, knowledge of the characterized nonlinear environment facilitates determination of an unknown input based on a measured output. Similarly, knowledge of the characterized nonlinear environment also facilitates formation of a desired output based on a configurable input. In both situations, the input thus characterized and the output thus obtained include features that would normally be lost in linear propagations. Such features can include evanescent waves and peripheral waves, such that an image thus obtained are inherently wide-angle, farfield form of microscopy.