A reinforcement device for an optical fiber fusion-spliced portion, which reinforces a fusion-spliced portion of optical fibers by heating and shrinking a reinforcement sleeve covering the fusion spliced portion, includes a heater configured to heat the reinforcement sleeve. The heater includes a sleeve housing portion capable of housing the reinforcement sleeve. The sleeve housing portion includes a first wall portion extending in a longitudinal direction of the sleeve housing portion and a second wall portion facing the first wall portion. The first wall portion and the second wall portion are configured such that a distance therebetween increases from a bottom portion side of the sleeve housing portion toward a top portion side of the sleeve housing portion in a cross-section orthogonal to the longitudinal direction. At least one bent portion is formed to at least one of the first wall portion and the second wall portion in the cross-section.

A fusion splicer is disclosed. The fusion splicer includes a fusion splicing unit that fusion splices of optical fibers, a communication unit that communicates through wireless connection with an external terminal, and a setting unit that sets a fusion condition of the fusion splicing unit. The communication unit acquires information related to the fusion condition of the fusion splicing unit from the external terminal. The setting unit sets the fusion condition of the fusion splicing unit based on the acquired information related to the fusion condition. The fusion splicing unit fusion splices in accordance with the fusion condition set by the setting unit.

An optical combiner includes: an optical fiber bundle formed by a plurality of first optical fibers; and a second optical fiber including an end surface joined to an end surface of the optical fiber bundle by fusion-splicing. The plurality of first optical fibers includes a predetermined first optical fiber and other first optical fibers. The predetermined first optical fiber is composed of one or more materials having higher softening temperatures than one or more materials of the other first optical fibers.

One or more embodiments of the disclosure relates to an end cap holder for fixing an end cap to aid in alignment with an optical fiber prior to splicing by a splicing device. The use of the end cap holder may provide a method to fix an end cap holder having a different diameter from an optical fiber that the splicing device may be set up or adjusted for.

A fiber structural body includes a first fiber, and a second fiber spliced to the first fiber such that light having propagated through the first fiber propagates through the second fiber. At least one of the fibers is a photonic crystal fiber. The second fiber is coated with a first coating layer and a second coating layer in order from a splice surface, and the first coating layer has a refractive index n.sub.1 larger than that of a clad layer of the second fiber. In the fiber structural body, L, r, n.sub.1, and NA satisfy a particular relationship.

An optical combiner 3 includes a plurality of incoming optical fibers 10, an outgoing optical fiber 20, and a plurality of bridge fibers 60, 50 provided between the plurality of incoming optical fibers 10 and the outgoing optical fiber 20, the plurality of bridge fibers 60, 50 being optically coupled to each other. In the bridge fibers 60, 50, a ratio of the outer diameter of a core 61, 51 to the outer diameter of a cladding 62, 52 is smaller in a bridge fiber located more apart from the incoming optical fiber 10.

A reinforcing sleeve is a member for collectively reinforcing spliced portions of a plurality of optical fiber core wires disposed side by side. The reinforcing member includes a heat-shrinkable tube, a heat-meltable member, a tension member, and so on. The heat shrinkable tube is a cylindrical member having an approximately circular cross section. The heat-meltable member, which is a first heat-meltable member, is in a cylindrical shape having an approximately circular or elliptical cross section. The tension member is a rod-shaped member. The tension member and the heat-meltable member are inserted into the heat-shrinkable member. A thick portion is provided at a substantially center portion of a width direction of the heat-meltable member. Thus, on a cross section perpendicular to a longitudinal direction of the heat-meltable member, an amount of the heat-meltable member at proximity of the center portion of the width direction of the heat-meltable member is greater than an amount of the heat-meltable member at proximity of the end portions of the width direction of the heat-meltable member. This forms a flow of the heat-meltable member from the center portion toward the end portions in the width direction at the time of melting the heat-meltable member.

An optical fiber splicing tray is disclosed. The optical fiber splicing tray may include: an optical fiber splicing tray body; and a marker detachably connected to the optical fiber splicing tray body, where the marker is arranged at a position facilitating observation and identification of the marker when a plurality of optical fiber splicing trays are stacked.

A pressure sensor includes: a light source that outputs signal light; a sensor optical fiber where the signal light is input and the signal light is propagated with a loss of 0.3 dB/m or more; and an optical receiver that receives the signal light propagated through the sensor optical fiber. Further, pressure applied to the sensor optical fiber is detected on a basis of intensity of the signal light received by the optical receiver.

The present disclosure relates to an optical fiber having a core and a cladding, where the cladding is doped with a dopant. The cladding has a dopant concentration gradient in the radial direction such that a concentration of the dopant changes with respect to radial distance from a core-cladding interface. Doping the cladding of the optical fiber enables ablation of the fiber surface with a line source to provide an ablated wedge or crack such that cleaving can be achieved by applying a stress force to the fiber after ablation or by applying a pull force during ablation.