Abstract: An optical fiber system exploits a principle of topological confinement for guided higher-order modes, in contrast to more conventional total-internal-reflection (TIR) confinement. The optical fiber has a geometry and index profile defining a cutoff wavelength for a predetermined L-mode of optical signal propagation in the optical fiber, where L is azimuthal mode index. An optical source subsystem is coupled to the optical fiber to establish an optical signal propagating in the optical fiber, wherein the optical signal has the predetermined L-mode and a wavelength being either (1) at least 15% above the cutoff wavelength such that the optical beam propagates as a topologically confined mode, or (2) sufficiently above the cutoff wavelength that, based on the L-mode of the optical beam, the optical beam propagates as a topologically confined mode having propagation loss less than 3 dB/meter.

Abstract: An optical fiber system exploits a principle of topological confinement for guided higher-order modes, in contrast to more conventional total-internal-reflection (TIR) confinement. The optical fiber has a geometry and index profile defining a cutoff wavelength for a predetermined L-mode of optical signal propagation in the optical fiber, where L is azimuthal mode index. An optical source subsystem is coupled to the optical fiber to establish an optical signal propagating in the optical fiber, wherein the optical signal has the predetermined L-mode and a wavelength being either (1) at least 15% above the cutoff wavelength such that the optical beam propagates as a topologically confined mode, or (2) sufficiently above the cutoff wavelength that, based on the L-mode of the optical beam, the optical beam propagates as a topologically confined mode having propagation loss less than 3 dB/meter.

Abstract: A vortex optical fiber for use in an illumination subsystem of an optical imaging system (e.g., a stimulated emission depletion (STED) microscopy system) includes an elongated optically transmissive medium having a set of regions including a core region, a trench region surrounding the core region, a ring region surrounding the trench region, and a cladding region, the set of regions having a doping profile providing a ?neff for vector modes in an LP11 mode group of greater than 1×10?4 in the visible spectral range so as to simultaneously guide stable Gaussian and orbital angular momentum (OAM) carrying modes at corresponding visible wavelengths.

Abstract: A system comprises an electromagnetic radiation source, a polarizing element, a mode converter, an optical fiber, and a measurement device. The polarizing element receives electromagnetic radiation produced by the electromagnetic radiation source and outputs linearly-polarized electromagnetic radiation having a linear polarization angle ?1. The mode converter converts the linearly-polarized electromagnetic radiation to an orbital angular momentum (OAM) mode of linearly-polarized electromagnetic radiation with topological charge Li. The OAM mode of linearly-polarized electromagnetic radiation is a superposition of first and second OAM modes with topological charges Li and opposite circular polarizations. The optical fiber supports propagation of the first and second OAM modes with an absolute effective index difference ?neff greater than or equal to 5×10?3, such that linearly-polarized electromagnetic radiation with linear polarization angle ?2 is emitted by the optical fiber.

Abstract: A system comprises an electromagnetic radiation source, a polarizing element, a mode converter, an optical fiber, and a measurement device. The polarizing element receives electromagnetic radiation produced by the electromagnetic radiation source and outputs linearly-polarized electromagnetic radiation having a linear polarization angle ?1. The mode converter converts the linearly-polarized electromagnetic radiation to an orbital angular momentum (OAM) mode of linearly-polarized electromagnetic radiation with topological charge Li. The OAM mode of linearly-polarized electromagnetic radiation is a superposition of first and second OAM modes with topological charges Li and opposite circular polarizations. The optical fiber supports propagation of the first and second OAM modes with an absolute effective index difference ?neff greater than or equal to 5×10?5, such that linearly-polarized electromagnetic radiation with linear polarization angle ?2 is emitted by the optical fiber.

Abstract: A higher-order-mode (HOM) fiber of a fiber laser has step index and guidance diameter (GD) defining wavelength-dependent dispersion characteristics and effective areas for corresponding HOMS of optical signal propagation. One HOM has anomalous dispersion and effective area defining a first wavelength and first power of a pulse optical signal for conversion to a second wavelength and second power by soliton self-frequency shifting (SSFS). By controlling step index and GD, the dispersion and effective area of a HOM are adjusted to bring the second wavelength into a desired range, enabling applications requiring non-conventional fiber laser wavelengths. HOMS may share a predetermined group index and group velocity at wavelengths established by a Raman gain peak to effect wavelength conversion by interpulse and intermodal Raman scattering, which may occur in a cascaded fashion to yield multicolor lasers with desired wavelengths, pulse energies and pulse widths.

Abstract: A higher-order-mode (HOM) fiber of a fiber laser has step index and guidance diameter (GD) defining wavelength-dependent dispersion characteristics and effective areas for corresponding HOMS of optical signal propagation. One HOM has anomalous dispersion and effective area defining a first wavelength and first power of a pulse optical signal for conversion to a second wavelength and second power by soliton self-frequency shifting (SSFS). By controlling step index and GD, the dispersion and effective area of a HOM are adjusted to bring the second wavelength into a desired range, enabling applications requiring non-conventional fiber laser wavelengths. HOMS may share a predetermined group index and group velocity at wavelengths established by a Raman gain peak to effect wavelength conversion by interpulse and intermodal Raman scattering, which may occur in a cascaded fashion to yield multicolor lasers with desired wavelengths, pulse energies and pulse widths.

Abstract: A vortex optical fiber for use in an illumination subsystem of an optical imaging system (e.g., a stimulated emission depletion (STED) microscopy system) includes an elongated optically transmissive medium having a set of regions including a core region, a trench region surrounding the core region, a ring region surrounding the trench region, and a cladding region, the set of regions having a doping profile providing a ?neff for vector modes in an LP11 mode group of greater than 1×10?4 in the visible spectral range so as to simultaneously guide stable Gaussian and orbital angular momentum (OAM) carrying modes at corresponding visible wavelengths.

Abstract: Described is an optical fiber system for delivering ultrashort pulses with minimal distortions due to nonlinearity. The system is based on delivering the optical pulses in a higher order mode (HOM) of a few-moded fiber. The fiber is designed so that the dispersion for the HOM is very large. This results in a dispersion length LD for the delivery fiber that is exceptionally small, preferably less than the non-linear length LNL. Under these conditions the system may be designed so the optical pulses experience minimum non-linear impairment, and short pulse/high peak power levels are reproduced at the output of the delivery fiber.

Abstract: A high-power fiber laser exploits efficiency and wavelength-conversion of nonlinear wave mixing in a higher-order mode (HOM) fiber providing large effective area and higher-power operation than single-order mode (SMF) fiber. In a “monomode” approach, mixing waves (pump(s), signal, idler) propagate in the same higher-order mode, and in an “intermodal” approach different waves propagate in different modes. The monomode approach can provide high-power wavelength conversion generating output in a desired band where good dopants may be unavailable. The intermodal approach demonstrates coherent combining of outputs of multiple lasers to generate high-power output in a desired band.

Abstract: A high-power fiber laser exploits efficiency and wavelength-conversion of nonlinear wave mixing in a higher-order mode (HOM) fiber providing large effective area and higher-power operation than single-order mode (SMF) fiber. In a “monomode” approach, mixing waves (pump(s), signal, idler) propagate in the same higher-order mode, and in an “intermodal” approach different waves propagate in different modes. The monomode approach can provide high-power wavelength conversion generating output in a desired band where good dopants may be unavailable. The intermodal approach demonstrates coherent combining of outputs of multiple lasers to generate high-power output in a desired band.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.

Abstract: Methods and systems are described using a non-linear optical system comprising a laser and a light delivery system comprising a single mode fiber, a mode converter, and a high order mode fiber, wherein the light delivery system that receives light from the source and provides a structured free-space beam having an embedded Gaussian beam. The light delivery system functions to illuminate a region of a sample and generate a non-linear response in a spatial region smaller than that associated with a Gaussian beam having a width comparable to the width of the embedded Gaussian beam. In another aspect, the light delivery system illuminates a region of a sample and generates a non-linear emission of radiation, is depicted. A further aspect of this embodiment includes an imaging assembly for detecting the non-linear emission and using a signal derived from the detected emission to generate a microscopic image of the sample.

Abstract: An arrangement for providing pulse compression at the output of an optical continuum source (advantageously used in spectral slicing applications) includes a section of higher-order mode (HOM) fiber configured to exhibit a predetermined dispersion in at least a portion of the predetermined wavelength range and an effective area greater than 40 ?m2, the dispersion of the HOM fiber selected to compensate for the dispersion introduced by the optical continuum source. The HOM fiber generates a compressed pulse output therefrom. An input mode converter is used to convert the created continuum from the fundamental mode associated with the conventional continuum sources to the higher-order mode(s) supported by the HOM fiber used to perform pulse compression. A bandpass filter is used to limit the bandwidth of the continuum signal to that associated with both the efficient conversion range of the mode converter and desired dispersion characteristic of the HOM fiber.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.

Abstract: A technique is described for generating a Bessel beam. An input optical fiber is provided that supports propagation in the fundamental mode. The input fiber is connected to a fiber mode converting device that provides phase matching, at a predetermined excitation wavelength, between the fundamental mode and a selected azimuthally symmetric higher-order mode. As an input to the fiber mode converting device, a coherent light beam is fed through the input optical fiber to provide a fundamental mode input at the excitation wavelength. The fiber mode converting device resonantly excites the selected azimuthally symmetric mode. The azimuthally symmetric mode is provided as a beam output from an endface of the fiber mode converting device to approximate a Bessel beam.

Abstract: An apparatus and method for producing optical pulses of a desired wavelength utilizes a section of higher-order-mode (HOM) fiber to receive input optical pulses at a first wavelength, and thereafter produce output optical pulses at the desired wavelength through soliton self-frequency shifting (SSFS) or Cherenkov radiation. The HOM fiber is configured to exhibit a large positive dispersion and effective area at wavelengths less than 1300 nm.

Abstract: Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.

Abstract: Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.

Abstract: Disclosed are optical fiber devices incorporating optical fibers with total dispersion greater than material dispersion, and with preferred dispersion values less than +50 ps/nm-km. The desired dispersion values are obtained when light resides substantially in a single higher order mode (HOM) of the fiber, typically the LP02 mode. The optical fibers also preferably have substantial separation between the effective indices of the HOM and any other mode.