Abstract: A mode division multiplexing system that includes a transmitter system, a receiver system and an optical link that optically connects the transmitter and receiver systems. The optical link includes a rectangular-core optical fiber having a rectangular core with a short dimension and a long dimension. The rectangular-core optical fiber supports only a single mode in the short dimension and multiple modes in the long dimension. A method of transmitting optical signals includes converting single mode optical signals to respective multimode optical signals each having a select spatial mode as defined by the rectangular-core optical fiber. The multimode optical signals are multiplexed and transmitted from the transmitter system to the receiver system over the rectangular-core optical fiber where the multimode optical signals are demultiplexed and converted back to single mode optical signals, which are then detected by respective receivers. A rectangular-core optical fiber is also disclosed.

Abstract: The single-mode optical fibers have a core region that includes an inner core region having a delta value ?1 and a radius r1 immediately surrounded by an outer core region of radius r2 and a delta value ?2<?1, wherein ?1-?2 is in the range from 0.3% to 2%. A cladding region of radius r3 immediately surrounds the core region. The inner and outer regions define an annular width ?r=r2?r1. At least one of r1, r2, ?r and r3 changes with a period p in the longitudinal direction between first and second values each having a corresponding level distance dF. The change occurs over a transition distance dT such that dT/dF<0.1. The Brillouin frequency shift ?f changes by an amount ?[?f] that is least 10 MHz over each period p, thereby allowing for Brillouin frequency-shift management in fiber-based sensor systems.

Abstract: Methods of manufacturing multi-mode optical fiber, and multi-mode optical fiber produced thereby, are disclosed. According to embodiments, a method for forming an optical fiber may include heating a multi-mode optical fiber preform and applying a draw tension to a root of the multi-mode optical fiber preform on a long axis of the multi-mode optical fiber preform thereby drawing a multi-mode optical fiber from the root of the multi-mode optical fiber preform. The draw tension may be modulated while the multi-mode optical fiber is drawn from the root of the multi-mode optical fiber preform. Modulating the draw tension introduces stress perturbations in the multi-mode optical fiber and corresponding refractive index perturbations in a core of the multi-mode optical fiber.

Abstract: Multicore optical fibers are disclosed that have randomly arranged cores within a cladding matrix. In some cases, the cores are defined by air lines formed in a glass matrix. The cores can have an edge-to-edge spacing designed so that the multicore optical fiber operates in either a weak-coupling regime or a strong-coupling regime. Imaging systems and optical fiber communication systems that utilize the multicore fibers disclosed here are also presented.

Abstract: A mode division multiplexing system that includes a transmitter system, a receiver system and an optical link that optically connects the transmitter and receiver systems. The optical link includes a rectangular-core optical fiber having a rectangular core with a short dimension and a long dimension. The rectangular-core optical fiber supports only a single mode in the short dimension and multiple modes in the long dimension. A method of transmitting optical signals includes converting single mode optical signals to respective multimode optical signals each having a select spatial mode as defined by the rectangular-core optical fiber. The multimode optical signals are multiplexed and transmitted from the transmitter system to the receiver system over the rectangular-core optical fiber where the multimode optical signals are demultiplexed and converted back to single mode optical signals, which are then detected by respective receivers. A rectangular-core optical fiber is also disclosed.

Abstract: Described herein are aqueous acidic glass etching solutions or media comprising HF and H2SO4, wherein HF is present in concentrations not exceeding about 1.3M. The etching solutions are used to treat glass articles such as thin glass sheets at above-ambient temperatures to etch slight thicknesses of surface glass therefrom, the etching solutions exhibiting improved stability against dissolved glass precipitation and rapid glass removal rates at slightly elevated temperatures.

Abstract: The single-mode optical fibers have a core region that includes an inner core region having a delta value ?1 and a radius r1 immediately surrounded by an outer core region of radius r2 and a delta value ?2<?1, wherein ?1-?2 is in the range from 0.3% to 2%. A cladding region of radius r3 immediately surrounds the core region. The inner and outer regions define an annular width ?r=r2?r1. At least one of r1, r2, ?r and r3 changes with a period p in the longitudinal direction between first and second values each having a corresponding level distance dF. The change occurs over a transition distance dT such that dT/dF<0.1. The Brillouin frequency shift ?f changes by an amount ?[?f] that is least 10 MHz over each period p, thereby allowing for Brillouin frequency-shift management in fiber-based sensor systems.

Abstract: A multicore fiber is provided that includes a plurality of elliptical cores spaced apart from one another. Each of the plurality of elliptical cores has an elliptical shape. The multicore fiber also includes a cladding surrounding the plurality of elliptical cores.

Abstract: A method is provided that includes: forming a low-index trench region with a first density; forming an inner barrier layer comprising silica around the trench region at a second density greater than the first density; depositing silica-based soot around the first barrier layer to form an overclad region at a third density less than the second density; inserting a core cane into a trench-overclad structure; forming an outer barrier layer comprising silica in an outer portion of the overclad region at a fourth density greater than the third density; flowing a down dopant-containing gas through the trench-overclad structure to dope the trench region with the down dopant, and wherein the barrier layers mitigate diffusion of the down-dopant into the overclad region; and consolidating the trench-overclad and the core cane.

Abstract: Multicore optical fibers are disclosed that have randomly arranged cores within a cladding matrix. In some cases, the cores are defined by air lines formed in a glass matrix. The cores can have an edge-to-edge spacing designed so that the multicore optical fiber operates in either a weak-coupling regime or a strong-coupling regime. Imaging systems and optical fiber communication systems that utilize the multicore fibers disclosed here are also presented.

Abstract: An optical fiber, comprising: (i) a core, (ii) a cladding surrounding the core, (iii) at least one stress member adjacent the fiber core and situated within the cladding, said stress member comprising silica doped with F.

Abstract: A method is provided that includes: forming a low-index trench region with a first density; forming an inner barrier layer comprising silica around the trench region at a second density greater than the first density; depositing silica-based soot around the first barrier layer to form an overclad region at a third density less than the second density; inserting a core cane into a trench-overclad structure; forming an outer barrier layer comprising silica in an outer portion of the overclad region at a fourth density greater than the third density; flowing a down dopant-containing gas through the trench-overclad structure to dope the trench region with the down dopant, and wherein the barrier layers mitigate diffusion of the down-dopant into the overclad region; and consolidating the trench-overclad and the core cane.

Abstract: A method of forming an optical fiber includes the steps of forming a soot blank of a silica-based cladding material, wherein the soot blank has a top surface and a bulk density of between 0.8 g/cm2 and 1.6 g/cm3. At least one hole is drilled in the top surface of the soot blank. At least one core cane member is positioned in the at least one hole. The soot blank and at least one soot core cane member are consolidated to form a consolidated preform. The consolidated preform is drawn into an optical fiber.

Abstract: A method for forming an optical glass preform from a soot preform is provided. The method includes forming a soot preform, placing the soot preform in a furnace, and applying a vacuum through a centerline hole of the soot preform.

Abstract: Described herein are aqueous acidic glass etching solutions or media comprising HF and H2SO4, wherein HF is present in concentrations not exceeding about 1.3M. The etching solutions are used to treat glass articles such as thin glass sheets at above-ambient temperatures to etch slight thicknesses of surface glass therefrom, the etching solutions exhibiting improved stability against dissolved glass precipitation and rapid glass removal rates at slightly elevated temperatures.

Abstract: Methods and apparatus for processing edge portions of a donor semiconductor wafer include controlling chemical mechanical polishing parameters to achieve chamfering of the edges of the donor semiconductor wafer; and alternatively or additionally flexing the donor semiconductor wafer to present a concave configuration, where edge portions thereof are pronounced as compared to a central surface area thereof, such that the pronounced edge portions of the donor semiconductor wafer are preferentially polished against a polishing surface in order to achieve the chamfering.

Abstract: Methods and apparatus for processing edge portions of a donor semiconductor wafer include controlling chemical mechanical polishing parameters to achieve chamfering of the edges of the donor semiconductor wafer; and alternatively or additionally flexing the donor semiconductor wafer to present a concave configuration, where edge portions thereof are pronounced as compared to a central surface area thereof, such that the pronounced edge portions of the donor semiconductor wafer are preferentially polished against a polishing surface in order to achieve the chamfering.

Abstract: Disclosed is a single mode optical waveguide fiber having a segmented core. The relative indexes, the refractive index profiles and the radii of the segments are chosen to provide waveguide fiber properties advantageously used in severe environments, such as, undersea cables. The segmented core waveguide fiber has a negative total dispersion over the operating window of about 1530 nm to 1570 nm, which serves to eliminate soliton formation. The key properties of dispersion zero, cut off wavelength, attenuation, and bend resistance fall within desired ranges. The waveguide also features a low polarization mode dispersion.