The present disclosure relates to a laser polishing apparatus where the laser beam emitted by the laser polishing apparatus can be configured to control the shape of the optical fiber end face. Stated another way, the laser polishing apparatus parameters can be adjusted such that the laser beam emitted can polish the optical fiber end face into a particular shape.

The present disclosure relates to a method of forming a tapered optical fiber, where the optical fiber has a cladding encasing a core and has an initial outer diameter. The method involves applying opposing forces to spaced apart sections of the optical fiber. The spaced apart sections define a length portion representing a waist region. While applying the opposing forces, simultaneously applying heat to the waist region to gradually produce a taper of the optical fiber within the waist region. The taper has a first diameter at a midpoint of the waist region which is less than the initial outer diameter. An etch operation is then performed by chemically etching at least a subportion of the waist region of the optical fiber to reduce the subportion to a second diameter which is less than the first diameter.

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.

The invention discloses an apparatus (100) to fabricate U-bent fiber optic sensors, transducers and waveguides, using laser assisted technologies as heat source. The apparatus includes a heating source (110) and a robotic articulate arm (130) that may modify the geometry of an optical fiber (150) with either silica or polymer cladding and fabricate sensor probes by decladding the polymeric cladding in addition to twisting and bending of the optical fiber in an automated manner. The geometry of the optical fiber sensor probe is controlled by the heating source (110), beam (112) thickness, exposure time of fiber and the positioning of a motorized stage. The advantage of the apparatus includes reduction in fabrication time, repeatable and controllable bend diameter for any size of optic fiber probes.

A device for fusion splicing, by an arc discharge, a pair or a plurality of pairs of optical fibers arranged so that end surfaces thereof face each other. An optical fiber arrangement portion positions the pair or the plurality of pairs of optical fibers between a pair of electrodes. A control portion controls a voltage applied to the pair of electrodes. The control portion generates a first discharge between the pair of electrodes, stops the first discharge between the pair of electrodes, and then generates an arc discharge between the pair of electrodes to fusion-splice the pair or the plurality of pairs of optical fibers to each other. A discharge time of the first discharge is 200 milliseconds or less. A time from stopping the first discharge to starting the arc discharge is 100 milliseconds or less.

Disclosed are a method of fixing an optical fiber and a measuring apparatus using the same, in which the method includes (a) heating a fixing portion where the optical fiber is to be fixed to an object, and (b) forming a concavo-convex structure by melting the heated fixing portion. The optical fiber is fixed to the object by filling an adhesive or filler in a state in which the fixing portion having the concavo-convex structure is disposed in an insertion space formed in the object. The optical fiber and the object can be firmly fixed using the mechanical coupling structure by forming the concavo-convex portion in a part where the optical fiber is to be fixed, and slip can be prevented from occurring between the cladding and the covering jacket.

A gain flattening filter includes a first optical fiber that has a core, a first cladding, and a second cladding and that has a uniform composition in a length direction; and a pair of second optical fibers fused to both ends of the first optical fiber. The first optical fiber has a first section in which a slanted refractive index grating is formed and a pair of second sections connecting both ends of the first section to the pair of second optical fibers. The first cladding contains a photosensitive material whose refractive index increases upon irradiation with light having a specific wavelength. In the core, a tensile stress remains in the first section. An average MFD of the second sections is larger than an average MFD of the second optical fibers and smaller than an average MFD of the first section.

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.

Provided is a method of manufacturing an optical device that includes a multicore fiber including a plurality of cores and a fan-in/fan-out device including single-core fibers that are respectively connected to the cores based on a plurality of connection combinations when the multicore fiber is rotated. The method includes: a first step of determining an optical loss for each of the cores while changing the connection combinations between the single-core fibers and the cores; and a second step of selecting one of the connection combinations according to a result of the first step and connecting an end portion of the multicore fiber and an end portion of the fan-in/fan-out device to connect the single-core fibers with the cores based on the one of the connection combinations.

A fiber bulge (“bulge”) formed in an end of an optical fiber for positioning the optical fiber in a ferrule bore is disclosed. An energy source is controlled to direct focused energy to the end of the optical fiber extended from the front end face of the ferrule to expose and melt the end of the optical fiber into a bulge of desired geometry and size. The bulge comprises a cross-sectional region having an outer surface having a minimum outer diameter larger than the inner diameter of the ferrule bore. Thus, the optical fiber may be pulled back in the ferrule bore such that at least a portion of the outer surface of the interface region of the bulge interferes with and engages the front opening of the ferrule bore to position the fiber core within the ferrule bore.