Abstract: Optical polarization-based devices and techniques are provided to enable low cost construction and easy signal processing to measure the light frequency via measurements of signals associated with a delay between the two orthogonal polarizations after passing through a DGD element and the retardation value of the DGD element without directly measuring the optical frequency. The optical detection may be designed in various configurations. In particular, for example, the optical detection may split the optical output of the DGD into two optical beams with two different optical detectors so that the final frequency information can be deducted into a pair of sine and cosine functions, such as a pair of sine and cosine functions of measured optical signal levels and the retardation value of the DGD element.

Abstract: Devices, systems and techniques for measuring optical polarization-related parameters in optical materials and devices such as polarization maintaining (PM) fiber links based on polarization crosstalks that spatially distribute over a length of a material such as a PM fiber link.

Abstract: This patent document discloses fiber sensing techniques and devices for shape monitoring by using single- and multi-core optical fiber implementations and optical interferometry. Implementations can be made based on coherent optical time domain reflectometry (OTDR) or optical frequency domain reflectometry (OFDR).

Abstract: The technology disclosed in this application provide for non-destructive and non-contact optical characterization of fiber reinforced plastic composites and other structures under test based on optical transmission scanning.

Abstract: The disclosed technology includes, among others, methods and devices for measuring distributed fiber bend or stress related characteristics along an optical path of fiber under test (FUT) uses both a light input unit and a light output unit connected to the FUT at one single end.

Abstract: Optical designs and techniques for providing compact optical delay lines by using a dual fiber collimator structured to include (1) an input fiber line that receives and guides an input light beam, (2) an output fiber line that guides and exports an output light beam that has an optical delay relative to the input light beam, and (3) a collimating lens placed on one side of end facets of the input and output fiber lines to receive the input light beam from the input fiber line and to output the output beam light to the output fiber line.

Abstract: The disclosed technology in this patent document includes, among others, methods and apparatus for distributed measuring at least one of fiber bend or stress related characteristics along an optical path of a fiber under test (FUT) using both a light input unit and a light output unit connected to the FUT at one single end.

Abstract: The disclosed technology includes, among others, methods and devices for measuring distributed fiber bend or stress related characteristics along an optical path of fiber under test (FUT) uses both a light input unit and a light output unit connected to the FUT at one single end.

Abstract: Techniques and devices for measuring polarization crosstalk in polarization maintaining fiber by placing the PM fiber in a 1-dimensional or 2-dimensional configuration for sensing stress or strain exerted on the PM fiber at different locations along the fiber with a high spatial sensing resolution.

Abstract: The disclosed technology in this patent document includes, among others, methods apparatus for distributed measuring at least one fiber bend or stress related characteristics along an optical path of fiber under test (FUT) uses both a light input unit and a light output unit connected to the FUT at one single end.

Abstract: Imaging devices and processing techniques based on imaging information along the depth direction in an optical coherent tomography (OCT) image are disclosed to enhance observed morphological features. The methods and systems obtain different OCT images of the target object under different reference path lengths, process the different OCT images to obtain a derivative with respect to the signal path length of image information of the different images, and processing the derivative to extract improved image information of the target object. The derivatives may be in a form related to a gradient value of the normalized OCT image intensity, or an attenuation coefficient.

Abstract: Techniques and devices for measuring stress, strain, or temperature based on polarization crosstalk analysis in birefringence optical birefringent media including polarization maintaining fiber. The disclosed techniques and devices can be implemented to measure polarization crosstalk distribution in polarization maintaining fiber by placing the PM fiber in a 1-dimensional or 2-dimensional configuration for sensing temperature, stress or strain in the PM fiber at different locations along the fiber with a high spatial sensing resolution. In some implementations, the disclosed techniques and devices can be implemented to simultaneously measure stress, strain and temperature from analyzing the probe light. For example, both temperature and stress/strain can be simultaneously measured by using the same sensors to extract and separate temperature measurements from stress/strain measurements.

Abstract: Techniques and devices for measuring polarization crosstalk in birefringence optical media including polarization maintaining fiber.

Abstract: Imaging devices and processing techniques based on imaging information along the depth direction in an optical coherent tomography (OCT) image are disclosed to enhance observed morphological features. The methods and systems obtain different OCT images of the target object under different reference path lengths, process the different OCT images to obtain a derivative with respect to the signal path length of image information of the different images, and processing the derivative to extract improved image information of the target object. The derivatives may be in a form related to a gradient value of the normalized OCT image intensity, or an attenuation coefficient.

Abstract: Techniques, devices and applications are provided for monitoring a polarization mode dispersion (PMD) effect in an optical signal.

Abstract: Techniques and devices use cascaded optical polarization devices having modulated optical retardation to control optical polarization of light and can be configured for polarization scrambling. Uniform rate scrambling and quasi-uniform rate scrambling modes are provided in described devices and rate-additive designs based on multiple cascaded devices are also disclosed to achieve high-speed scrambling.

Abstract: Techniques and devices for measuring polarization crosstalk in birefringence optical media including polarization maintaining fiber.

Abstract: Techniques and devices for measuring the distribution of polarization crosstalk in birefringence optical media including polarization maintaining fiber based on suppressing the number and magnitude of ghost interference peaks.

Abstract: Techniques, devices and applications are provided for monitoring a polarization mode dispersion (PMD) effect in an optical signal.

Abstract: Techniques and devices use cascaded optical polarization devices having modulated optical retardation to control optical polarization of light and can be configured for polarization scrambling. Uniform rate scrambling and quasi-uniform rate scrambling modes are provided in described devices and rate-additive designs based on multiple cascaded devices are also disclosed to achieve high-speed scrambling.