A hollow-core photonic crystal fiber (HC-PCF) (10) for guiding at least one mode of a light field (1) along a mode guiding section (11) of the HC-PCF (10), comprises an outer jacket (12), an inner cladding (13) and a hollow core (14), which extend along the HC-PCF (10), wherein the inner cladding (13) is arranged on an interior surface of the outer jacket (12) and comprises anti-resonant structures (15) surrounding the hollow core (14), and the hollow core (14) has a mode guiding core diameter (d) provided along the mode guiding section of the HC-PCF (10), and wherein at least one fiber end (16) of the HC-PCF (10) has a light field coupling section (17) in which the hollow core (14) is tapered over an axial coupling section length from a fiber end core diameter (D) at the at least one fiber end (16) to the mode guiding core diameter (d). Furthermore, methods of using the HC-PCF and manufacturing the HC-PCF are described.

A method for fixing a single-mode fiber to a multimode fiber comprises the following steps: injecting light radiation into the injection end of the single-mode fiber and positioning the junction ends of the single-mode fiber and of the multimode fiber relative to one another so as to propagate at least part of the light radiation in the multimode fiber; modally decomposing the light radiation collected at the injection end of the multimode fiber and measuring a quantity representative of the optical power present in a first group of secondary modes; and adjusting the relative position of the junction ends and freezing them with respect to one another in a determined relative coupling position. Coupling equipment for carrying out the fixing method is also disclosed.

A method for fixing a single-mode fiber to a multimode fiber comprises the following steps: injecting light radiation into the injection end of the single-mode fiber and positioning the junction ends of the single-mode fiber and of the multimode fiber relative to one another so as to propagate at least part of the light radiation in the multimode fiber; modally decomposing the light radiation collected at the injection end of the multimode fiber and measuring a quantity representative of the optical power present in a first group of secondary modes; and adjusting the relative position of the junction ends and freezing them with respect to one another in a determined relative coupling position. Coupling equipment for carrying out the fixing method is also disclosed.

The present invention relates to an optical shape sensor (OS), comprising an optical fiber (F2) having a length defining a longitudinal direction, the optical fiber (F2) having at least two fiber cores (C21, C22) extending along the length of the optical fiber (F2), an optical coupling member (OCM2) arranged at a proximal optical fiber end of the optical fiber (F2), the coupling member (OCM2) having a first distal end face (OF2) optically connected to the proximal optical fiber end, and a proximal second end face (IF2) spaced apart from the first distal end face (OF2) in the longitudinal direction of the optical fiber (F2), the optical coupling member (OCM2) being configured to couple light into each of the fiber cores (C21, C22, C23). An optical interface (OI) at a transition from the optical coupling member (OCM2) to the proximal optical fiber end is partially reflective and substantially transmissive, wherein the optical interface (OI) is arranged in such a distance distally from the proximal second end face (IF2) and is configured such that light interface is reflected at the optical interface (OI) with a reflection intensity distribution which substantially does not overlap with a reflection intensity distribution of light reflected at the second end face (IF2) of the optical coupling member (OCM2).

A method for manufacturing an optical fiber, the method including: a stripping step of partially stripping a coating layer of the optical fiber; a splicing step of fusion-splicing an exposed end surface of a glass fiber; and a recoating step of recoating a protective resin covering a stripped portion of the coating layer and an exposed portion of the glass fiber, in which the stripping step is a step of irradiating the coating layer with a laser light to strip the coating layer.

A fusion splicing device is disclosed that includes a connector that fusion splices a pair of optical fibers and a glass clamp that clamps a glass part that has been removed of a coating of the optical fiber, where the glass clamp is provided at an outer side of the connector. The fusion splicing device further includes a coating clamp that clamps at least a part of the coating of the optical fiber and is provided at an outer side of the glass clamp. The fusion splicing device also includes a wind protector cover that covers the connector, the glass clamp, and the coating clamp. Additionally, the fusion splicing device includes a heater that heats a protection sleeve covered on a fusion splice point of the optical fibers that have been fusion spliced with the connector and an aligner that aligns fingertips holding the optical fiber.

A fiber module (1B) according to the present disclosure includes an input-side optical fiber (11), an output-side optical fiber (12), a ferrule (20) in which the input-side optical fiber and the output-side optical fiber are insertable in both ends and a groove (32) is formed in a direction orthogonal to a longitudinal direction (D1) in the middle of the longitudinal direction, a dielectric multilayer film filter (30) inserted in the groove, and an input-side GI fiber (15) and an output-side GI fiber (16) joined by fusion to respective terminal portions of the input-side optical fiber and the output-side optical fiber. The dielectric multilayer film filter is interposed between an end surface (15f) of the input-side GI fiber and an end surface (16f) of the output-side GI fiber in the longitudinal direction.

A portable device for attaching a connector to an optical fiber, the optical fiber having an end, the device comprising means for receiving the optical fiber at the end of the optical fiber; and a connector station for autonomously attaching the connector to the optical fiber.

As described herein, a mode field adapter (MFA) comprises a first fiber including a core associated with a fundamental mode field diameter and a cladding with a diameter that decreases toward a waist. The MFA comprises a second fiber including a core associated with a fundamental mode field diameter that matches the fundamental mode field of the first fiber at the waist and a cladding with a diameter that matches the diameter of the cladding of the first fiber at the waist and increases from the waist of the second fiber. The cladding of the first fiber may be adiabatically etched such that a core-to-cladding ratio of the first fiber changes over a length of the first fiber, and the core and the cladding of the second fiber may be adiabatically tapered such that a core-to-cladding ratio of the second fiber is constant over a length of the second fiber.

There is described a multi-clad optical fiber for propagating an optical signal having at least a single mode. The multi-clad optical fiber generally has a fiber core, an inner cladding surrounding the fiber core, and at least an outer cladding surrounding the inner cladding, the multi-clad optical fiber having at least a taper portion extending along a longitudinal dimension z, the taper portion having a radial dimension progressively decreasing at a normalized slope exceeding an adiabaticity criterion of a conventional single-clad optical fiber propagating at least the single-mode across its single-mode core.