Abstract: Aspects of the present application relate to techniques of diagnosing whether a pathogen (e.g., SARS-CoV-2) is present in a subject using infrared (IR) spectroscopy and machine learning techniques. The techniques use spectral data obtained from performing IR spectroscopy on a biological sample (e.g., saliva or nasal sample, or genetic material extracted therefrom) to generate a set of feature values. The feature values are provided as input to a machine learning model to obtain output indicating whether the pathogen is present in the biological sample. The output of the machine learning model may be used to determine a diagnosis result for a subject.

Abstract: Aspects of the present application relate to techniques of diagnosing whether a pathogen (e.g., SARS-CoV-2) is present in a subject using infrared (IR) spectroscopy and machine learning techniques. The techniques use spectral data obtained from performing IR spectroscopy on a biological sample (e.g., saliva or nasal sample, or genetic material extracted therefrom) to generate a set of feature values. The feature values are provided as input to a machine learning model to obtain output indicating whether the pathogen is present in the biological sample. The output of the machine learning model may be used to determine a diagnosis result for a subject.

Abstract: An all-fiber, all-states of polarization linear design depolarizer is provided. It is made of two polarization combiners (PC1,PC2) with a 2×2 directional coupler (DC) between them. The connections between the coupler (DC) and the two polarization combiners (PC1,PC2) have optical phase delays (L1,L2) and half wave polarization rotators (PR1,PR2,PR3) to make proper adjustments.

Abstract: An all-fiber, all-states of polarization linear design depolarizer is provided. It is made of two polarization combiners (PC1,PC2) with a 2×2 directional coupler (DC) between them. The connections between the coupler (DC) and the two polarization combiners (PC1,PC2) have optical phase delays (L1,L2) and half wave polarization rotators (PR1,PR2,PR3) to make proper adjustments.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.

Abstract: An all-fiber broadband polarization combiner is disclosed based on a Mach-Zehnder (MZ) structure. The entry coupler to the MZ is a polarization pump combiner (PPC) and the exit coupler is a wavelength division multiplexer (WDM) coupler. The two couplers are interconnected with two standard SM fibers which form the arms of the central zone of the MZ. Two polarization maintaining (PM) fibers are spliced to the two input arms of the PPC and are oriented so that polarization X in one PM fiber is orthogonal to polarization Y in the other PM fiber. And the MZ is induced with a phase shift ?? of ? between the two arms of the central zone.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.

Abstract: An all-fiber broadband polarization combiner is disclosed based on a Mach-Zehnder (MZ) structure. The entry coupler to the MZ is a polarization pump combiner (PPC) and the exit coupler is a wavelength division multiplexer (WDM) coupler. The two couplers are interconnected with two standard SM fibers which form the arms of the central zone of the MZ. Two polarization maintaining (PM) fibers are spliced to the two input arms of the PPC and are oriented so that polarization X in one PM fiber is orthogonal to polarization Y in the other PM fiber. And the MZ is induced with a phase shift ?? of ? between the two arms of the central zone.

Abstract: An all-fiber depolarizer having a linear design includes a directional coupler associated with a polarization combiner. Linear light is pumped into the coupler where its intensity is split in two. Between the coupler and the combiner there is included an optical delay and the polarization of one intensity is made orthogonal to the other, as they enter the polarization combiner. The combiner combines the orthogonal polarizations and the light exits by an output in a depolarized state.

Abstract: An all-fiber depolarizer having a linear design includes a directional coupler associated with a polarization combiner. Linear light is pumped into the coupler where its intensity is split in two. Between the coupler and the combiner there is included an optical delay and the polarization of one intensity is made orthogonal to the other, as they enter the polarization combiner. The combiner combines the orthogonal polarizations and the light exits by an output in a depolarized state.

Abstract: A method of adjusting thermal dependence of an optical fiber involves hydrogenating the fiber to render it photosensitive, and then exposing it to UV radiation for such time period as to achieve the desired adjustment in the thermal dependence. In an all-fiber Mach-Zehnder interferometer, the method involves using a photosensitive fiber as one of the arms of the interferometer and exposing this photosensitive fiber to UV radiation so as to adjust the thermal dependence of the interferometer. The resulting interferometer is also part of the invention.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.