Disclosed is an annular-beam coupling system enabling reduction of noise generated from a core of a double-clad fiber. The disclosed annular-beam coupling system comprises: a fiber for transmitting light of a light source; a collimator for receiving the light outputted from the fiber and forming a parallel beam of a circular shape; an annular-beam generation unit for converting the parallel beam into an annular beam; and a double-clad fiber having the annular beam coupled to a cladding region thereof.

There is provided a system for measuring temperature and strain simultaneously utilizing Brillouin Scattering within an optical fiber. The system has a cladding, a first optical core within the cladding and a second optical core within the cladding and having a different refractive index profile and/or composition than the first core. Means to couple light into and out of said individual optical cores and/or from one optical core to the other within the fiber is provided along with means for calculating strain and temperature characteristics based on measured Brillouin frequencies for said optical cores.

Some embodiments of the disclosure provide an optical fiber Fabry-Perot sensor (1), and a manufacturing method thereof. According to an embodiment, the optical fiber Fabry-Perot sensor (1) includes a hollow tube body (10), a first optical fiber (20), and a second optical fiber (30). The hollow tube body (10) has a first tube body (11), a cavity portion (12), and a second tube body (13) sequentially arranged in an axial direction. The first optical fiber (20) is provided within the first tube body (11) in the axial direction and has a first light guide end face (21) provided within the cavity portion (12). The second optical fiber (30) is provided in the second tube body (13) in the axial direction and has a second light guide end face (31) provided within the cavity portion (12).

An optical fiber device may include a unitary core including a primary section and a secondary section, wherein at least a portion of the secondary section is offset from a center of the unitary core, wherein the unitary core twists about an optical axis of the optical fiber device along a length of the optical fiber device, and wherein a refractive index of the primary section is greater than a refractive index of the secondary section; and a cladding surrounding the unitary core.

A micro-fluidic reactor may comprise a photosensitive glass substrate with a plurality of features produced by etching. The features may include micro-channels, micro-lenses, and slots for receiving optical fibers. During operation of the micro-fluidic reactor, the optical fibers may transmit optical signals for measuring characteristics of fluid reagents and reactions taking place. The micro-lenses may focus optical signals from the optical fibers to create an approximately collimated optical path for the optical signals, reducing optical spread and enhancing fiber-to-fiber optical power coupling.

An optical delay line device, providing a fixed or variable optical delay, including an optical input, an optical output, an optical assembly that directs a beam along an optical path from the input to the output. The optical assembly including; a retroreflector, an optical element including first, second and third reflective surfaces, the second and third reflective surfaces being arranged to make therebetween an angle of 45, a beam that propagates along the optical path and enters the optical element being reflected by the first surface with an angle of 90 toward the second surface, then being reflected by the second and third surfaces to exit from the optical element in a direction parallel to the direction of the beam incident on the optical element, and said optical element is arranged so as to steer said output beam onto said second surface of said retroreflector.

An optical fiber device may include a unitary core including a primary section and a secondary section, wherein at least a portion of the secondary section is offset from a center of the unitary core, wherein the unitary core twists about an axis of the optical fiber device along a length of the optical fiber device, and wherein a refractive index of the primary section is greater than a refractive index of the secondary section; and a cladding surrounding the unitary core.

An optical fiber laser device generates laser light by using an optical amplifying fiber as an amplification medium in a laser oscillator and includes: an optical outputting fiber configured to emit laser light to an outside; a return-light-attenuating portion configured to perform an attenuation process to return light propagating through at least the optical outputting fiber in a reverse direction of the laser light; a thermal conversion unit provided at the return-light-attenuating portion and configured to convert the return light into heat; a temperature-monitoring device configured to measure an increase in a temperature, of the return-light-attenuating portion, caused by the heat converted by the thermal conversion unit; and a control unit configured to decrease or stop an output of the laser light when the temperature measured by the temperature-monitoring device becomes a predetermined threshold temperature or higher.

The present disclosure provides a preparation method of an optical fiber device having a polymer micronano structure integrated in an optical fiber, the method comprising: welding a hollow optical fiber so that the hollow optical fiber is welded between two solid optical fibers, ablating the welded hollow optical fiber utilizing a femtosecond laser ablation technology so that a channel vertical to an inner wall is ablated on the hollow optical fiber, filling a colorless and transparent liquid photoresist material inside the hollow optical fiber which has been ablated so that the inside of the hollow optical fiber is filled with the photoresist material, and polymerizing on the photoresist material inside the hollow optical fiber utilizing a femtosecond laser two-photon polymerization technology.

A method of preparing an optical connector located within a gap between a first optical assembly and a second optical assembly is provided. The optical connector includes a contrast layer having at least one cured bridge portion and at least one uncured portion formed from a first composition having a first refractive index (RI.sup.1). The method comprises applying a second composition having a second refractive index (RI.sup.2) on the contrast layer to form a second layer and mixing at least a portion of the second layer with the at least one uncured portion of the contrast layer to form at least one intermixed portion having a third refractive index (RI.sup.3), wherein R|.sup.1>R|.sup.3>RI.sup.2, and then curing the intermixed portion and optional second layer such that each one of the at least one cured bridge portions is surrounded by an intermixed portion and optional second layer.