Abstract: An optical fiber apparatus and a method of recovering radiation-induced-attenuation (RIA) onto a rare-earth-doped optical fiber under irradiation are provided in this disclosure. A light source is coupled to a rare-earth doped optical fiber. The light source emits a combination of mode locked pulsed light and non-mode locked quasi-continuous-wave light. The mode locked pulsed light are used to recover RIA onto the rare-earth doped optical fiber in real time, and the non-mode locked light are used to pump the rare-earth doped optical fiber as a gain medium. Each pulsed duration of the mode locked pulsed light is much shorter than operation duration of the non-mode locked light, such that an instantaneous power of the mode locked pulsed light exceeds a saturated pumping power required for the rare-earth doped optical fiber, so as to effectively elevate the core temperature of rare-earth doped fiber to achieve a confined photo-annealed recovery of RIA onto rare-earth doped fibers.

Abstract: A robust broadband ASE (amplified spontaneous emission) fiber light source device outputs a light beam which is little affected by temperature and radiation. The light source device is a single-pass backward or double-pass backward architecture, and has a coolerless pump laser and temperature compensated bandpass reflector. The light source device may have a high pass filtering element disposed between the wavelength division multiplexer thereof and the optical isolator thereof, so as to compensate the effect of the temperature to the mean wavelength of the light beam. The specific band of the temperature compensated bandpass reflector which reflects the light beam, and the band which the high pass filtering element transmits the light beam are within the band which the ASE unit amplifies the light beam, and the high pass filtering element mainly absorbs the light beam outside the specific band.

Abstract: An optical fiber apparatus and a method of recovering radiation-induced-attenuation (RIA) onto a rare-earth-doped optical fiber under irradiation are provided in this disclosure. A light source is coupled to a rare-earth doped optical fiber. The light source emits a combination of mode locked pulsed light and non-mode locked quasi-continuous-wave light. The mode locked pulsed light are used to recover RIA onto the rare-earth doped optical fiber in real time, and the non-mode locked light are used to pump the rare-earth doped optical fiber as a gain medium. Each pulsed duration of the mode locked pulsed light is much shorter than operation duration of the non-mode locked light, such that an instantaneous power of the mode locked pulsed light exceeds a saturated pumping power required for the rare-earth doped optical fiber, so as to effectively elevate the core temperature of rare-earth doped fiber to achieve a confined photo-annealed recovery of RIA onto rare-earth doped fibers.

Abstract: This invention revealed and demonstrated a method of measuring and deriving a Jones Matrix of a fiber or fiber component, and to compensate the fiber or fiber component such that the fiber or fiber component plus the compensated optical circuit act as if an Unitary Matrix free space condition. In this way, all compensated fibers or fiber components act the same no matter what their original conditions are. It greatly enhances the fiber or fiber component repeatability and stability throughout the fiber or fiber component production line. The compensated circuit for Unitary Matrix can be applied externally or internally.

Abstract: An optical fiber apparatus is suitable to operate under irradiation, more particularly to mitigating the damage of a rare-earth-doped optical fiber element as part of an optical fiber assembly causes by irradiation. The irradiation mitigation attributes to a photo-annealing apparatus including at least a shorter wavelength photo-annealing spectral content, which is relative to that of a pump light source, for effectively photo-annealing the rare-earth-doped fiber element. Photo-annealing by such shorter wavelength light results in a fast and nearly complete recovery of radiation induced attenuation of the rare-earth-doped optical fiber element in the wavelength range from 900 nm to 1700 nm.

Abstract: A robust broadband ASE (amplified spontaneous emission) fiber light source device outputs a light beam which is little affected by temperature and radiation. The light source device is a single-pass backward or double-pass backward architecture, and has a coolerless pump laser and temperature compensated bandpass reflector. The light source device may have a high pass filtering element disposed between the wavelength division multiplexer thereof and the optical isolator thereof, so as to compensate the effect of the temperature to the mean wavelength of the light beam. The specific band of the temperature compensated bandpass reflector which reflects the light beam, and the band which the high pass filtering element transmits the light beam are within the band which the ASE unit amplifies the light beam, and the high pass filtering element mainly absorbs the light beam outside the specific band.

Abstract: This patent disclosure is based on a silicon, instead of LiNbO3, waveguide chip. The disclosed silicon-based multi-function integrated-optic chip comprises a unique design and fabrication features onto it. A unique polarization-diversity coupler is designed and fabricated to couple the external light into the silicon waveguide structure. A unique two-step (vertical and lateral) taper waveguide region is designed and fabricated to bridge the polarization-diversity coupler output with the input of a multi-mode interferometer (MMI) splitter for power loss reduction. At either end of the Y-junction output, there is a phase modulator to achieve optical phase modulation through various physics mechanisms. With this newly-developed silicon-based multi-function integrated optic chip, the size and cost of fiber sensors including FOG's can be greatly reduced.

Abstract: This patent disclosure is based on silicon instead of LiNbO3, waveguide chip. The disclosed silicon-based multi-function integrated-optic chip comprises of unique design and fabrication features onto it. First, a unique polarization-diversity coupler is designed and fabricated to couple the external light into the silicon waveguide structure. Then TE mode is guided into a silicon slab waveguide, but TM mode is confined and diverted 90 degree in a silicon carbide structure till the chip edges for TM-mode suppression. Second, a unique two-step (vertical and lateral) taper waveguide region is designed and fabricated to bridge the polarization-diversity coupler output with the input of a multi-mode interferometer (MMI) splitter for power loss reduction. In this configuration, MMI may be a 1×2 or 2×2 structure to divide the input TE mode into a 50/50 splitting ratio output to form a Y-junction.

Abstract: This invention relates to a near real time optical compensation verification system for verifying a fiber or fiber component through internal or external compensation to achieve equivalently free space propagation of a broadband light when coupled into fiber. Preferably, no component is added to the fiber or fiber component, and the compensation method is realized through real time fiber bending, twisting or other means at either or both ends of a fiber or fiber component. The output optical characteristics of the compensated fiber or fiber component are measured by a polarimeter through changing the input light properties. The required multi-variable compensation to achieve Unitary Matrix free space condition is computed in near real time, and as the feedback to formulate the required compensation. The disclosed invention not only enhances yield in the fiber and fiber component, but also accelerates the optimization of optical fiber sensors employed free space fiber coil.

Abstract: This patent disclosure is based on a silicon, instead of LiNbO3, waveguide chip. The disclosed silicon-based multi-function integrated-optic chip comprises a unique design and fabrication features onto it. A unique polarization-diversity coupler is designed and fabricated to couple the external light into the silicon waveguide structure. A unique two-step (vertical and lateral) taper waveguide region is designed and fabricated to bridge the polarization-diversity coupler output with the input of a multi-mode interferometer (MMI) splitter for power loss reduction. At either end of the Y-junction output, there is a phase modulator to achieve optical phase modulation through various physics mechanisms. With this newly-developed silicon-based multi-function integrated optic chip, the size and cost of fiber sensors including FOG's can be greatly reduced.

Abstract: An optical fiber apparatus is suitable to operate under irradiation, more particularly to mitigating the damage of a rare-earth-doped optical fiber element as part of an optical fiber assembly causes by irradiation. The irradiation mitigation attributes to a photo-annealing apparatus including at least a shorter wavelength photo-annealing spectral content, which is relative to that of a pump light source, for effectively photo-annealing the rare-earth-doped fiber element. Photo-annealing by such shorter wavelength light results in a fast and nearly complete recovery of radiation induced attenuation of the rare-earth-doped optical fiber element in the wavelength range from 900 nm to 1700 nm.

Abstract: An optical fiber apparatus is suitable to operate under irradiation, more particularly to mitigating the damage of a rare-earth-doped optical fiber element as part of an optical fiber assembly causes by irradiation. The irradiation mitigation attributes to a photo-annealing apparatus including at least a shorter wavelength photo-annealing spectral content, which is relative to that of a pump light source, for effectively photo-annealing the rare-earth-doped fiber element. Photo-annealing by such shorter wavelength light results in a fast and nearly complete recovery of radiation induced attenuation of the rare-earth-doped optical fiber element in the wavelength range from 900 nm to 1700 nm.

Abstract: This patent disclosure is based on silicon instead of LiNbO3, waveguide chip. The disclosed silicon-based multi-function integrated-optic chip comprises of unique design and fabrication features onto it. First, a unique polarization-diversity coupler is designed and fabricated to couple the external light into the silicon waveguide structure. Then TE mode is guided into a silicon slab waveguide, but TM mode is confined and diverted 90 degree in a silicon carbide structure till the chip edges for TM-mode suppression. Second, a unique two-step (vertical and lateral) taper waveguide region is designed and fabricated to bridge the polarization-diversity coupler output with the input of a multi-mode interferometer (MMI) splitter for power loss reduction. In this configuration, MMI may be a 1×2 or 2×2 structure to divide the input TE mode into a 50/50 splitting ratio output to form a Y-junction.

Abstract: This invention revealed and demonstrated a method of measuring and deriving a Jones Matrix of a fiber or fiber component, and to compensate the fiber or fiber component such that the fiber or fiber component plus the compensated optical circuit act as if an Unitary Matrix free space condition. In this way, all compensated fibers or fiber components act the same no matter what their original conditions are. It greatly enhances the fiber or fiber component repeatability and stability throughout the fiber or fiber component production line. The compensated circuit for Unitary Matrix can be applied externally or internally. For the external approach, for example, compensators such as variable retarder and half-wave plate may be added, or equivalently polarization controllers may be employed. For the internal approach, no component is added, and the compensation is realized through fiber bending, twisting or other means at either or both ends of a fiber or fiber component.

Abstract: An optical fiber apparatus is suitable to operate under irradiation, more particularly to mitigating the damage of a rare-earth-doped optical fiber element as part of an optical fiber assembly causes by irradiation. The irradiation mitigation attributes to a photo-annealing apparatus including at least a shorter wavelength photo-annealing spectral content, which is relative to that of a pump light source, for effectively photo-annealing the rare-earth-doped fiber element. Photo-annealing by such shorter wavelength light results in a fast and nearly complete recovery of radiation induced attenuation of the rare-earth-doped optical fiber element in the wavelength range from 900 nm to 1700 nm.

Abstract: A method and system for adjusting power at output ports of a wavelength division multiplexing (WDM) coupler. A loss element may be placed at one or more of the output ports of the WDM coupler. The loss element may have a filter characteristic that matches the temperature sensitivity coefficient of the WDM coupler. The filter characteristic may reject power at one of the two output ports as a function of temperature. As a result, the loss element may balance the power at the output ports of the WDM coupler despite temperature variations.

Abstract: An example of a fiber optic light source has a pump laser that feeds light to a length of doped optical fiber. The optical fiber produces light that has a mean wavelength, for example in the range of 1515 nm to 1544 nm, such that the light is substantially unaffected when exposed to weapons level radiation.

Abstract: A method and system for adjusting power at output ports of a wavelength division multiplexing (WDM) coupler. A loss element may be placed at one or more of the output ports of the WDM coupler. The loss element may have a filter characteristic that matches the temperature sensitivity coefficient of the WDM coupler. The filter characteristic may reject power at one of the two output ports as a function of temperature. As a result, the loss element may balance the power at the output ports of the WDM coupler despite temperature variations.

Abstract: A new apparatus and method designed to protect an interferometric fiber optic light source from weapons level radiation threat is provided. A fiber optic light source is configured to produce a light spectrum which has a mean wavelength which is substantially unaffected when exposed to weapon's level radiation threat. The fiber optic light source is configured to produce a light output with a mean wavelength in the range of 1520 nm to 1540 nm, and is preferably configured to produce a light output with mean wavelength of about 1532 nm. The fiber optic light comprises a pump laser and a length of doped fiber optic material through which light from the pump laser is directed. The length of fiber optic material has a configuration which produces a light output with a predetermined spectrum and mean wavelength. The length of fiber optic material will depend on the specific properties of the fiber, but with the preferred material, i.e.

Abstract: A gyroscope having three fiber optic loops for sensing rates of rotation in three axes orthogonal to one another. The gyroscope has one or two detectors and one source that is shared among the three fiber optic sensing loop subsystems with a special multi-coupler configuration. Also, portions of the rotation rate signal processing electronics, whether an open or closed loop configuration, are shared among the three sensing loops. The gyroscope may be a single mode optical fiber depolarized configuration or a polarization maintaining optical fiber configuration.