There is provided a method of manufacturing an optical connector, including: preparing a multi-core optical fiber including a glass fiber and a resin coating that covers the glass fiber; inserting the glass fiber exposed from the resin coating into the ferrule such that the glass fiber protrudes from an end surface of a ferrule by a length A; rotating and aligning the multi-core optical fiber with respect to the ferrule; fixing the multi-core optical fiber to the ferrule; and so as to scrap off a tip end of the ferrule by a length. A deviation angle in the circumferential direction between a first initial end surface of the one end of the prepared glass fiber and a cross section of the glass fiber separated from the initial end surface by a length A+B mm is equal to or less than 0.9.

Disclosed is an optical fiber processing apparatus comprising: an optical fiber machining head provided with a fiber proceeding tunnel, through which an optical fiber passes, and a plurality of processing rod insertion holes formed in the circumference of the proceeding tunnel in a direction perpendicular to the tunnel; a processing rod having a machining tip for processing the optical fiber in the proceeding tunnel through the processing rod insertion hole; and an actuator operating a processing drill.

There is provided a method to fabricate optical taps and waveguide devices in photonic crystal fibers and other fibers with hollow structures. The method involves a preparation step, where the hollow holes inside the fiber are collapsed or partially modified locally; and a waveguide fabrication step, where a femtosecond laser is focused inside the fiber and used to produce optical waveguides that interact in the region that was previously modified in the preparation step.

There is provided a photonic bandgap fiber used in a state in which at least a part of the photonic bandgap fiber is bent at radii of 15 cm or greater and 25 cm or less. A large number of high refractive index portions 57 are disposed in a nineteen-cell core type in three layers, and a V value is 1.5 or greater and 1.63 or less. In the high refractive index portions 57, conditions are defined that a relative refractive index difference is % and a lattice constant is m so as to remove light in a higher mode at the bent portion as described above.

The present invention relates to a glass fiber (1) comprising at least one fiber core (10), at least one fiber cladding (11) which at least substantially encloses the fiber core (10) in the circumferential direction (U) and along the longitudinal axis (X), and at least one fiber coating (12) which substantially encloses the fiber cladding (11) in the circumferential direction (U) and along the longitudinal axis (X), wherein the glass fiber (1) has at least one first exposed portion (13a) where the fiber cladding (11) is exposed by the fiber coating (12), for removing light (B) at least from the fiber cladding (11), wherein at least the fiber cladding (11) has a plurality of recesses (14) at least substantially in the radial direction (R), which recesses are designed to at least partially discharge the light (B) at least from the fiber cladding (11). The glass fiber (1) is characterized in that the recesses (14), as longitudinal recesses (14), are each formed at least in portions precisely along the longitudinal axis (X).

A mode control system and method for controlling an output mode of a broadband radiation source including a photonic crystal fiber (PCF). The mode control system includes at least one detection unit configured to measure one or more parameters of radiation emitted from the broadband radiation source to generate measurement data, and a processing unit configured to evaluate mode purity of the radiation emitted from the broadband radiation source, from the measurement data. Based on the evaluation, the mode control system is configured to generate a control signal for optimization of one or more pump coupling conditions of the broadband radiation source. The one or more pump coupling conditions relate to the coupling of a pump laser beam with respect to a fiber core of the photonic crystal fiber.