A multi-core optical amplifying fiber includes: core portions doped with a rare-earth element; an inner cladding portion; and an outer cladding portion. A mode field diameter of each core portion at a wavelength at which the rare-earth element performs optical amplification is 5 μm to 11 μm, a relative refractive-index difference of the maximum refractive index of each core portion with respect to the inner cladding portion is 0.35% to 2%, a core-to-core distance is set such that total inter-core crosstalk is −40 dB/100 m or lower in an optical amplification wavelength band subjected to the optical amplification, a cladding thickness is smaller than a value obtained by adding the mode field diameter to a minimum value of the core-to-core distance, and a ratio of a total sectional area of the core portions to a sectional area of the inner cladding portion is 1.9% or more.

In various embodiments, the beam parameter product and/or numerical aperture of a laser beam is adjusted utilizing a step-clad optical fiber having a central core, a first cladding, an annular core, and a second cladding.

A method for displaying virtual content to a user, the method includes determining an accommodation of the user's eyes. The method also includes delivering, through a first waveguide of a stack of waveguides, light rays having a first wavefront curvature based at least in part on the determined accommodation, wherein the first wavefront curvature corresponds to a focal distance of the determined accommodation. The method further includes delivering, through a second waveguide of the stack of waveguides, light rays having a second wavefront curvature, the second wavefront curvature associated with a predetermined margin of the focal distance of the determined accommodation.

A medical device that includes a carrier member, one or more operative components disposed in the carrier member, an optical fiber at least partly disposed in the carrier member, and at least one fiber Bragg grating (FBG) sensor array associated with the optical fiber and disposed in the carrier member. The carrier member includes an insertion end and side walls that contact the subject's body during positioning of the carrier member in the subject's body. The at least one FBG sensor array measures contact forces at one or both of the insertion end and along the side walls of the carrier member during positioning of the carrier member in the subject's body. A multi-core optical fiber configured for use in a medical device for positioning in a subject's body is also provided. A system and method for guiding positioning of a medical device in a subject's body is also provided.

Provided are a monitoring device, a monitoring method, and an optical transmission system which are adapted for an increase in the number of cores of a multi-core optical fiber transmission path and suitable for crosstalk monitoring. The monitoring device monitors a multi-core optical fiber transmission path having a plurality of use cores and at least one or more non-use cores, and comprises: an applying means for applying, at a start point of the multi-core optical fiber transmission path, dithering to signal light propagating in the use cores; a monitoring means for monitoring the power of the non-use cores at an input side of a relay in the multi-core optical fiber transmission path; and a separating means for separating a monitoring result from the monitoring means into power components from the plurality of use cores.

A network device includes an enclosure, a multi-chip module (MCM), an optical-to-optical connector, and a multi-core fiber (MCF) interconnect. The enclosure has a panel. The MCM is inside the enclosure. The optical-to-optical connector, which is mounted on the panel of the enclosure, is configured to transfer a plurality of optical communication signals. The MCF interconnect has a first end coupled to the MCM and a second end connected to the optical-to-optical connector on the panel, for routing the plurality of optical communication signals between the MCM and the panel.

Described herein are systems, methods, and articles of manufacture for reducing coupling loss between optical fibers, more particularly, to reducing coupling loss between a hollow-core optical fiber (HCF) and another fiber, such as solid core fibers (SCF), through the use of mismatched mode field diameter (MFD) and optical connector assemblies for low latency patchcords. According to one embodiment, an article is configured to reduce a coupling loss between multiple optical fibers, wherein the article includes an HCF supporting the propagation of a first mode and an SCF coupled to the HCF. According to a further embodiment, a method is described for reducing the coupling loss or splicing loss between optical fibers, such as an exemplary HCF and a solid core SMF. These exemplary articles and methods may include coupling/splicing an exemplary HCF to an exemplary SMF with significantly smaller MFD as well as a splice-on-connector (SOC) assembly including a bridge fiber spliced between the HCF and the SCF, wherein the bridge fiber has a third MFD that is greater than the second MFD and smaller than the first MFD. Additional embodiments may feature a SCF having a second MFD at the proximal end and a third MFD at the distal end, wherein the second MFD is greater than the third MFD, and the third MFD is no greater than 90% of the first MFD of the HCF.

A multicore fiber includes: a cladding; and three or more and five or less cores disposed at rotationally asymmetric positions on a circumference centered at a center of the cladding. No core is disposed at the center of the cladding. Angles formed by adjacent ones of lines connecting the center of the cladding and respective ones of the cores are all larger than 60°.

A fiber includes M primary cores and N redundant cores, where M an integer is greater than two and N is an integer greater than one. Interferometric circuitry detects interferometric pattern data associated with the M primary cores and the N redundant cores when the optical fiber is placed into a sensing position. Data processing circuitry calculates a primary core fiber bend value for the M primary cores and a redundant core fiber bend value for the N redundant cores based on a predetermined geometry of the M primary cores and the N redundant cores in the fiber and detected interferometric pattern data associated with the M primary cores and the N redundant cores. The primary core fiber bend value and the redundant core fiber bend value are compared in a comparison. The detected data for the M primary cores is determined reliable or unreliable based on the comparison. A signal is generated in response to an unreliable determination.

Described are optical fibers and scanning fiber displays comprising optical fibers. The disclosed optical fibers include a plurality of mass adjustment regions, such as gas-filled regions, positioned between a central waveguiding element and an outer periphery for reducing a mass of the optical fiber as compared to an optical fiber lacking the plurality of mass adjustment regions.