Abstract: The present technology provides large mode area optical fibers engineered to have normal dispersion around 1600 nm, enabling high power Raman amplification at eye safer wavelengths. The fibers can have a main core and one or more side cores disposed relative to the main core so that modes of the main core and the one or more side cores hybridize into supermodes with modified dispersion.

Abstract: The present disclosure relates to a method of forming a tapered optical fiber, where the optical fiber has a cladding encasing a core and has an initial outer diameter. The method involves applying opposing forces to spaced apart sections of the optical fiber. The spaced apart sections define a length portion representing a waist region. While applying the opposing forces, simultaneously applying heat to the waist region to gradually produce a taper of the optical fiber within the waist region. The taper has a first diameter at a midpoint of the waist region which is less than the initial outer diameter. An etch operation is then performed by chemically etching at least a subportion of the waist region of the optical fiber to reduce the subportion to a second diameter which is less than the first diameter.

Abstract: The present disclosure relates to a method of forming a tapered optical fiber, where the optical fiber has a cladding encasing a core and has an initial outer diameter. The method involves applying opposing forces to spaced apart sections of the optical fiber. The spaced apart sections define a length portion representing a waist region. While applying the opposing forces, simultaneously applying heat to the waist region to gradually produce a taper of the optical fiber within the waist region. The taper has a first diameter at a midpoint of the waist region which is less than the initial outer diameter. An etch operation is then performed by chemically etching at least a subportion of the waist region of the optical fiber to reduce the subportion to a second diameter which is less than the first diameter.

Abstract: An all fiber wavelength selective coupler provides wavelength selective transfer of optical energy between two or more separated waveguides. The coupler includes signal cores that are separated enough that they can be fusion spliced to standard fibers as lead-in and lead-out pigtails. A bridge between the signal cores facilitates transfer of the optical energy through a process of evanescent coupling. In one example, the bridge is formed of a series of graded index cores.

Abstract: The present technology provides large mode area optical fibers engineered to have normal dispersion around 1600 nm, enabling high power Raman amplification at eye safer wavelengths. The fibers can have a main core and one or more side cores disposed relative to the main core so that modes of the main core and the one or more side cores hybridize into supermodes with modified dispersion.

Abstract: A class of fibers is described that have a non-circular cross section on one or both ends that can by optimized to capture the optical radiation from a laser diode or diode array and deliver the light in the same or different shape on the opposite end of the fiber. A large multimode rectangular waveguide may be provided which can accept the radiation from a high-power diode bar and transform it into a circular cross section on the opposite end, while preserving brightness.

Abstract: An all fiber wavelength selective coupler provides wavelength selective transfer of optical energy between two or more separated waveguides. The coupler includes signal cores that are separated enough that they can be fusion spliced to standard fibers as lead-in and lead-out pigtails. A bridge between the signal cores facilitates transfer of the optical energy through a process of evanescent coupling. In one example, the bridge is formed of a series of graded index cores.

Abstract: An Nd3+ optical fiber laser and amplifier operating in the wavelength range from 1300 to 1450 nm is described. The fiber includes a rare earth doped optical amplifier or laser operating within this wavelength band is based upon an optical fiber that guides light in this wavelength band. The waveguide structure attenuates light in the wavelength range from 850 nm to 950 nm and from 1050 nm to 1150 nm.

Abstract: Rare earth doped fiber lasers can be robust and efficient sources of high quality light, but are usually limited to the highest gain transitions of the active species. But rare earths typically possess a multitude of potentially useful transitions that might be accessed if the dominant transition can be suppressed. In fiber lasers this suppression is complicated by the very high net gain the dominant transitions exhibit; effective suppression requires some mechanism distributed along the length of the fiber. We have developed a novel waveguide with resonant leakage elements that frustrate guidance at well-defined and selectable wavelengths. Based on this waveguide, we have fabricated a Large Mode Area Neodymium doped fiber with suppression of the four-level transition around 1060 nm, and demonstrated lasing on the three-level transition at 930 nm with good efficiency.

Abstract: Rare earth doped fiber lasers can be robust and efficient sources of high quality light, but are usually limited to the highest gain transitions of the active species. But rare earths typically possess a multitude of potentially useful transitions that might be accessed if the dominant transition can be suppressed. In fiber lasers this suppression is complicated by the very high net gain the dominant transitions exhibit; effective suppression requires some mechanism distributed along the length of the fiber. We have developed a novel waveguide with resonant leakage elements that frustrate guidance at well-defined and selectable wavelengths. Based on this waveguide, we have fabricated a Large Mode Area Neodymium doped fiber with suppression of the four-level transition around 1060 nm, and demonstrated lasing on the three-level transition at 930 nm with good efficiency.

Abstract: An Nd3+ optical fiber laser and amplifier operating in the wavelength range from 1300 to 1450 nm is described. The fiber includes a rare earth doped optical amplifier or laser operating within this wavelength band is based upon an optical fiber that guides light in this wavelength band. The waveguide structure attenuates light in the wavelength range from 850 nm to 950 nm and from 1050 nm to 1150 nm.