Abstract: Various embodiments relate to a method including: coupling one or more optical spatial pilot signals into a first end of optical fiber, wherein the optical fiber is a multimode optical fiber; Reflecting and modifying each mode of the optical pilot signals at a second end of the optical fiber; receiving a reflected portion of the one or more optical spatial pilot signals at the first end of the of the optical fiber in response to the reflected portion having propagated through the optical fiber in both directions; processing the reflected spatial pilot to determine components of one of a round-trip transfer matrix of the optical fiber and a single-direction transfer matrix of the optical fiber.

Abstract: An optical apparatus includes a front optics section and a spectrometer section. The front optics section includes a spot de-multiplexer configured to receive a plurality of multi-mode optical signals each having a plurality of modal components, and to output in a linear array of a corresponding plurality of optical beams for each multimode optical signal. The spectrometer section includes a wavelength steering element configured to separate each of the optical beams into a plurality of wavelength channels. A fiber steering element is configured to steer the wavelength channels between the optical beams.

Abstract: Various embodiments relate to a method including: coupling one or more optical spatial pilot signals into a first end of optical fiber, wherein the optical fiber is a multimode optical fiber; Reflecting and modifying each mode of the optical pilot signals at a second end of the optical fiber; receiving a reflected portion of the one or more optical spatial pilot signals at the first end of the of the optical fiber in response to the reflected portion having propagated through the optical fiber in both directions; processing the reflected spatial pilot to determine components of one of a round-trip transfer matrix of the optical fiber and a single-direction transfer matrix of the optical fiber.

Abstract: An apparatus, including: an optical sensor fiber having a first end optically couplable to receive light from a light source, wherein the optical sensor fiber is a multimode optical fiber configured to carry light in different spatial propagating modes, wherein the optical sensor fiber is constructed such that environmental fluctuations couple light energy between some of the spatial propagating modes; a spatial propagating mode demultiplexer optically coupled to a second end the optical sensor fiber and configured to separate a plurality of light signals received from different ones of the spatial propagating modes; and an optical receiver configured to process the separated light signals and to estimate a longitudinal position of one of the environmental fluctuations along the optical sensor fiber based a measured delay between arrival times of the separated light signals.

Abstract: Disclosed herein are various embodiments of an optical cross-connect switch in which optical beamforming is used to generate desired (e.g., technically beneficial) beam profiles at the beam-steering element of the switch. An example beam profile that can be generated in this manner is a substantially rectangular beam profile generated from an input optical beam having a substantially Gaussian beam profile. The use of rectangular beam profiles may be beneficial because such beam profiles can be used to increase the optical fill factor of the beam-steering element of the switch, thereby enabling the switch to have a higher number of optical ports and/or a lower cost per optical port than comparable conventional optical cross-connect switches. In an example embodiment, the disclosed optical cross-connect switch can be used to implement a wavelength-selective optical router.

Abstract: We disclose a vertical-cavity surface-emitting laser (VCSEL) whose optical resonator can support multiple transverse resonator modes. The VCSEL has a plurality of electrodes that can apply individually controllable electrical currents to the active semiconductor region of the optical resonator and be configured to excite, e.g., a single selected transverse resonator mode or a desired linear combination of transverse resonator modes. In some embodiments, the VCSEL's optical resonator may have an effective lateral geometric shape that causes the excitable transverse resonator modes to correspond to the waveguide modes of a cylindrical optical fiber.

Abstract: An optical apparatus includes a front optics section and a spectrometer section. The front optics section includes a spot de-multiplexer configured to receive a plurality of multi-mode optical signals each having a plurality of modal components, and to output in a linear array of a corresponding plurality of optical beams for each multimode optical signal. The spectrometer section includes a wavelength steering element configured to separate each of the optical beams into a plurality of wavelength channels. A fiber steering element is configured to steer the wavelength channels between the optical beams.

Abstract: An apparatus includes a plurality of VCSELs, a master laser, one or more electrical drivers, and an optical combiner. The master laser is configured to transmit laser light to the VCSELs to optically lock wavelengths of the VCSELs. The one or more electrical drivers are connected to directly electrically modulate the VCSELs in a manner responsive to one or more digital data stream. The optical combiner is configured to combine light received from, at least, a pair of the VCSELs into an optical carrier with a substantially phase digital data modulation.

Abstract: We disclose a vertical-cavity surface-emitting laser (VCSEL) whose optical resonator can support multiple transverse resonator modes. The VCSEL has a plurality of electrodes that can apply individually controllable electrical currents to the active semiconductor region of the optical resonator and be configured to excite, e.g., a single selected transverse resonator mode or a desired linear combination of transverse resonator modes. In some embodiments, the VCSEL's optical resonator may have an effective lateral geometric shape that causes the excitable transverse resonator modes to correspond to the waveguide modes of a cylindrical optical fiber.

Abstract: An apparatus includes an optical fiber bundle that includes a plurality of input optical fibers and a tapered segment. One end of each of the input optical fibers physically connects to a wide end of the tapered segment. The optical fiber bundle is an integral unit. The input optical fibers are multimode optical fibers. Fundamental optical propagating modes of at least two of the multimode optical fibers have different velocities.

Abstract: Disclosed herein are various embodiments of an optical cross-connect switch in which optical beamforming is used to generate desired (e.g., technically beneficial) beam profiles at the beam-steering element of the switch. An example beam profile that can be generated in this manner is a substantially rectangular beam profile generated from an input optical beam having a substantially Gaussian beam profile. The use of rectangular beam profiles may be beneficial because such beam profiles can be used to increase the optical fill factor of the beam-steering element of the switch, thereby enabling the switch to have a higher number of optical ports and/or a lower cost per optical port than comparable conventional optical cross-connect switches. In an example embodiment, the disclosed optical cross-connect switch can be used to implement a wavelength-selective optical router.

Abstract: An optical amplifier includes a multi-mode pump laser module, a multi-mode waveguide, a multi-mode to multiple single-mode fiber converter module and a plurality of single-mode cores. The multi-mode pump laser module emits pump light having a plurality of modes to the multi-mode fiber or waveguide. The multi-mode waveguide propagates the emitted pump light to the converter module. The converter module receives the pump light and distributes the pump light approximately uniformly to a plurality of single-mode cores.

Abstract: A photonic lantern spatial multiplexer that provides mode selectivity includes a multimode optical waveguide and a plurality of single mode optical waveguides. The single mode cores of the single mode optical waveguides merge with the multimode core of the multimode optical waveguide. At least two of the single mode cores have different respective single mode effective refractive indexes.

Abstract: A wavelength-selective cross-connect (WSXC) device configured to route any set of carrier wavelengths from a corresponding input port to any selected output port. The WSXC device comprises a diffraction grating and a beam-steering device optically coupled to one another and to the input/output ports using astigmatic optics. The astigmatic optics includes one or more cylindrical lenses configured to image one beam-steering surface onto another beam-steering surface to enable a continuous spectral response. The astigmatic optics may further include (i) a cylindrical Fourier lens that enables the WSXC device to convert a change in the angular beam steering performed by the beam-steering device into a corresponding image-spot displacement at the output ports and/or (ii) one or more cylindrical lenses configured to image the active surface of the beam-steering device onto the diffraction grating. Various unfolded configurations of the various embodiments of the WSXC device are also disclosed.

Abstract: Various exemplary embodiments relate to an optical amplifier, including: a multicore rare-earth doped optical fiber with a first plurality of cores associated with a first stage of the optical amplifier and a second plurality of cores associated with a second stage of the optical amplifier; a three dimensional (3D) waveguide configured to couple input space division multiplexed (SDM) channels into the first plurality of cores at a first end of the multicore rare-earth doped optical fiber and to couple channels from the second plurality of cores to output SDM channels; a reflector configured to optically interconnect the first plurality of cores to the second plurality of cores; and pump laser coupled to the multicore rare-earth doped optical fiber configured to produce laser pump light to pump the multicore rare-earth doped optical fiber.

Abstract: An apparatus includes a plurality of input optical couplers and a plurality of output optical couplers. The input optical couplers are placed in a pattern to receive light from multiple locations of an end face of an input multimode optical fiber (MMOF). The output optical couplers are placed in a pattern to provide light to multiple locations of an end face of an output MMOF. The apparatus further includes a plurality of single-mode optical paths. Each of the paths is connected to a corresponding one of the input optical couplers and a corresponding one of the output optical couplers.

Abstract: An apparatus includes an optical fiber bundle that includes a plurality of input optical fibers and a tapered segment. One end of each of the input optical fibers physically connects to a wide end of the tapered segment. The optical fiber bundle is an integral unit. The input optical fibers are multimode optical fibers. Fundamental optical propagating modes of at least two of the multimode optical fibers have different velocities.

Abstract: An optical apparatus includes a front optics section and a spectrometer section. The front optics section includes a spot de-multiplexer configured to receive a plurality of multi-mode optical signals each having a plurality of modal components, and to output in a linear array of a corresponding plurality of optical beams for each multimode optical signal. The spectrometer section includes a wavelength steering element configured to separate each of the optical beams into a plurality of wavelength channels. A fiber steering element is configured to steer the wavelength channels between the optical beams.

Abstract: An optical amplifier includes a multi-mode pump laser module, a multi-mode waveguide, a multi-mode to multiple single-mode fiber converter module and a plurality of single-mode cores. The multi-mode pump laser module emits pump light having a plurality of modes to the multi-mode fiber or waveguide. The multi-mode waveguide propagates the emitted pump light to the converter module. The converter module receives the pump light and distributes the pump light approximately uniformly to a plurality of single-mode cores.

Abstract: Various exemplary embodiments relate to an optical amplifier, including: a multicore rare-earth doped optical fiber with a first plurality of cores associated with a first stage of the optical amplifier and a second plurality of cores associated with a second stage of the optical amplifier; a three dimensional (3D) waveguide configured to couple input space division multiplexed (SDM) channels into the first plurality of cores at a first end of the multicore rare-earth doped optical fiber and to couple channels from the second plurality of cores to output SDM channels; a reflector configured to optically interconnect the first plurality of cores to the second plurality of cores; and pump laser coupled to the multicore rare-earth doped optical fiber configured to produce laser pump light to pump the multicore rare-earth doped optical fiber.