A structured surface reduces optical reflectance at a predetermined wavelength in a first wavelength range extending from 600 nm to 1700 nm. The structured surface includes a plurality of parallel linear structures arranged along a first direction and extending along an orthogonal second direction. Each linear structure includes opposing nonlinear facets meeting at a peak extending along the second direction. An average spacing between the peaks of adjacent linear structures is less than the predetermined wavelength, such that for light having the predetermined wavelength and incident on the structured surface in a direction substantially perpendicular to the first and second directions, the structured surface has a reflectance Rx<0.5% for light polarized along the first direction and a reflectance Ry<0.5% for light polarized along the second direction, where an absolute value of Rx−Ry is less than 0.3%. An optical ferrule may have an exit surface that includes the structured surface.

To provide an optical connector that can prevent degradation of end faces of cores using a simple structure. The optical connector is adapted to connect single-mode optical fibers for visible light with a wavelength of less than or equal to 650 nm to ultraviolet light, specifically, connect the optical fibers by allowing ferrules having fixed thereto the respective optical fibers to be inserted into a sleeve and allowing the ferrules to butt against each other, in which a film of nitride, oxide, or fluoride is formed on an end face of each of the optical fibers and the ferrules.

A ferrule mold having a reverse-image of a through-hole array for optical fibers is formed. A non-polymeric ferrule material is deposited in the reverse-image mold, followed by removing the mold to create a multi-fiber connector ferrule having at least two fiber through-holes. An optical fiber is inserted in each through-hole until each fiber endface is positioned approximately even with a connection surface of the ferrule. A fiber recess for each of the optical fibers is formed such that each fiber is recessed from the multi-fiber ferrule connection surface by a distance of at least 0.1 micron. The recess may be formed by differential polishing of the non-polymeric ferrule and endfaces of the optical fibers. Alternatively, a layer of spacer material may be deposited over the multi-fiber ferrule connection surface. An antireflection coating is deposited over the ferrule connection surface and ends of the recessed fibers.

An optical connector includes: an optical waveguide substrate including a plurality of core regions and a cladding layer covering the plurality of core regions; a first ferrule including a first housing portion that houses the optical waveguide substrate; a second ferrule facing the first ferrule and including a second housing portion that houses a multi-core optical fiber including a plurality of first cores and a first cladding covering the plurality of first cores; and a first positioning mechanism configured to determine a position of the second ferrule with respect to the first ferrule and fix the first ferrule and the second ferrule to each other such that the first ferrule and the second ferrule are separable from each other. The second ferrule is disposed such that each of the plurality of core regions is optically connected to a corresponding one of the plurality of first cores via a gap.

A ferrule mold having a reverse-image of a through-hole array for optical fibers is formed. A non-polymeric ferrule material is deposited in the reverse-image mold, followed by removing the mold to create a multi-fiber connector ferrule having at least two fiber through-holes. An optical fiber is inserted in each through-hole until each fiber endface is positioned approximately even with a connection surface of the ferrule. A fiber recess for each of the optical fibers is formed such that each fiber is recessed from the multi-fiber ferrule connection surface by a distance of at least 0.1 micron. The recess may be formed by differential polishing of the non-polymeric ferrule and endfaces of the optical fibers. Alternatively, a layer of spacer material may be deposited over the multi-fiber ferrule connection surface. An antireflection coating is deposited over the ferrule connection surface and ends of the recessed fibers.

An angle polished fiber optic connector adapted for connection with another angle polished connector in two, reversed configurations has a connector body and first and second angle polished ferrules. The first ferrule is supported by the connector body in a first fixed rotational position about the longitudinal axis of the first ferrule, and the second ferrule is supported by the connector body in a second fixed rotational position about the longitudinal axis of the second ferrule. The second fixed rotational position of the second ferrule being offset by 180 degrees from the first fixed rotational position of the first ferrule. A method of making an angled polished fiber optic connector that can be connected with different polarities is also disclosed.

A ferrule includes a ferrule matrix, an optical fiber, and a dielectric reflective film. The optical fiber is disposed in an accommodating through hole of the ferrule matrix, and the dielectric reflective film covers an optical transmission surface of the optical fiber and a surface that is of the ferrule matrix and that faces a matching ferrule. The dielectric reflective film has a through hole, such that the dielectric reflective film does not shield a main optical path area of the optical transmission surface of the optical fiber. A reflective band of the dielectric reflective film includes at least a part of a communication band of the optical fiber. In this way, when light from the matching ferrule is transmitted to the ferrule matrix and the optical fiber, the dielectric reflective film reflects the light.

A multi-fiber push on (MPO) optical connector includes a housing supporting a ferrule body. The ferrule body forms an optical connection with a second MPO optical connector. The ferrule body includes a connection end having a distal end face arranged to face the second MPO optical connector when the ferrule body forms the optical connection with the second MPO optical connector. The connection end of the ferrule body defines a recess extending proximally into the ferrule body from the distal end face. A plurality of optical fibers are received in the ferrule body. Distal ends of the optical fibers are adjacent to a proximal end of the recess such that the distal ends of the optical fibers are spaced apart from the second MPO optical connector when the ferrule body forms an optical connection with the second MPO optical connector. The distal ends of the optical fibers are coated with an anti-reflective material.

An optical connector includes: an optical waveguide substrate including a plurality of core regions and a cladding layer covering the plurality of core regions; a first ferrule including a first housing portion that houses the optical waveguide substrate; a second ferrule facing the first ferrule and including a second housing portion that houses a multi-core optical fiber including a plurality of first cores and a first cladding covering the plurality of first cores; and a first positioning mechanism configured to determine a position of the second ferrule with respect to the first ferrule and fix the first ferrule and the second ferrule to each other such that the first ferrule and the second ferrule are separable from each other. The second ferrule is disposed such that each of the plurality of core regions is optically connected to a corresponding one of the plurality of first cores via a gap.

A ferrule mold having a reverse-image of a through-hole array for optical fibers is formed. A non-polymeric ferrule material is deposited in the reverse-image mold, followed by removing the mold to create a multi-fiber connector ferrule having at least two fiber through-holes. An optical fiber is inserted in each through-hole until each fiber endface is positioned approximately even with a connection surface of the ferrule. A fiber recess for each of the optical fibers is formed such that each fiber is recessed from the multi-fiber ferrule connection surface by a distance of at least 0.1 micron. The recess may be formed by differential polishing of the non-polymeric ferrule and endfaces of the optical fibers. Alternatively, a layer of spacer material may be deposited over the multi-fiber ferrule connection surface. An antireflection coating is deposited over the ends of the recessed fibers.