The optical fiber coupler array can be capable of providing a low-loss, high-coupling coefficient interface with high accuracy and easy alignment between a plurality of optical fibers (or other optical devices) with a first channel-to-channel spacing, and an optical device having a plurality of closely-spaced waveguide interfaces with a second channel-to-channel spacing, where each end of the optical fiber coupler array can be configurable to have different channel-to-channel spacing, each matched to a corresponding one of the first and second channel-to-channel spacing. Advantageously, the refractive indices and sizes of both inner and outer core, and/or other characteristics of vanishing core waveguides in the optical coupler array can be configured to reduce the back reflection for light propagating from the plurality of the optical fibers at the coupler first end to the optical device at the coupler second end, and/or vice versa.

A waveguide comprises an un-tapered end and a tapered end. The waveguide progressively varies a numerical aperture (NA) of light as the light propagates from the tapered end to the un-tapered end.

Methods and apparatus are provided for a monolithic multi-optical-waveguide penetrator or connector. One example apparatus generally includes a plurality of large diameter optical waveguides, each having a core and a cladding, and a body having a plurality of bores with the optical waveguides disposed therein, wherein at least a portion of the cladding of each of the optical waveguides is fused with the body, such that the apparatus is a monolithic structure. Such an apparatus provides for a cost- and space-efficient technique for feedthrough of multiple optical waveguides. Also, the body may have a large outer diameter which can be shaped into features of interest, such as connection alignment or feedthrough sealing features.

The invention concerns an apparatus and its use for laser processing. The invention also concerns a method and an optical component. According to the invention, at a first laser device, providing a first optical feed fiber and a second laser device providing a second optical feed fiber is provided. A beam combining means connected to the first and second feed fibers and to a multi-core optical fiber is adapted to form a composite laser beam by having the first optical feed fiber aligned with a first core of the multi-core optical fiber and the second optical feed fiber aligned with at least one second core of the multi-core optical fiber. The first and second cores outputs a composite laser beam to a workpiece to be processed. A control unit controls power density of at least one of first and second laser beams of the composite laser beam in at least one of: in response to approaching a change point in direction of cutting progression and to cause change in relation between the power density of the first output laser beam and power density of the second output laser beam in accordance with thickness of the workpiece being cut.

A multichannel optical coupler array can include a coupler housing structure and longitudinal waveguides. At least one of the longitudinal waveguides can be a vanishing core waveguide having an inner vanishing core having a first refractive index (N-1), an outer core having a second refractive index (N-2), and an outer cladding having a third refractive index (N-3). A refractive index transition between N-1 and N-2 can have a function form N(r), where r is a transverse distance from the inner vanishing core center. The function N(r) can be a smooth function having a positive average of the second derivative or function N(r) can be a step function with at least one step approximating the smooth function. The coupler housing structure may have non-circular holes formed by convex-shaped housing structure elements.

A high power optical fiber laser combiner includes a plurality of input port fibers; an output port fiber including a cladding and a propagating layer, the cladding being used to clad the propagating layer, and the cladding including a micro-nano structure on a surface thereof for removing a residual power in the cladding; and a bundling portion for bundling the input port fibers, and the input port fibers spliced to the output port fiber. The heat effect accumulation of laser power on the cladding can effectively be reduced by the micro-nano structure of the high power optical fiber laser combiner. The tolerant power and bundling power of the optical fiber laser combiner can be raised to increase the output power of the optical laser.

The present invention comprises a core (11) and a primary coating (12) that is lower in refractive index than the core (11) and that covers the side surface of the core (11) except in a coating-removed section (I0). The side surface of the core (11), in at least part of the coating-removed section (I0), is covered with an intermediate-refractive-index resin part (14) that is lower in refractive index than the core (11) and that is higher in refractive index than the primary coating (12).

Method for adapting a fiber beam combiner to transmit at least 20 kW of optical power without noticeable bulk material damage mechanism effect and destructive nonlinearities, the method comprising: connecting an adiabatic beam combiner with a splice connection to an input facet of a graded index fiber which has a core doped with an index increasing material, further comprising the step(s) of: restricting the numerical aperture of the graded index fiber, and/or selecting the index increasing material with a Raman gain lower than that of GeO.sub.2 such as Al2O3 or Y2O3, and/or placing a shroud tube around the graded index fiber core, said shroud tube comprising a fluorine-doped silica tube.

The present disclosure provides an optical equalizer for photonics system in an electric-optical communication network. The optical equalizer includes an input port and an output port. Additionally, the optical equalizer includes a filter having a number of stages coupled to each other in a multi-stage series with an output terminal of any stage being coupled to an input terminal of an adjacent next stage while the input terminal of a first stage of the multi-stage series being coupled from the input port. Each stage includes a tap terminal configured to pass an optical power factored by a coefficient of multiplication from the corresponding input terminal of the stage to a tap-output path characterized by a corresponding phase delay. Furthermore, the optical equalizer includes a combiner configured to sum up the optical powers respectively from the number of tap-output paths of the multi-stage series to the output port.

A high power optical fiber laser combiner includes a plurality of input port fibers; an output port fiber including a cladding and a propagating layer, the cladding being used to clad the propagating layer, and the cladding including a micro-nano structure on a surface thereof for removing a residual power in the cladding; and a bundling portion for bundling the input port fibers, and the input port fibers spliced to the output port fiber. The heat effect accumulation of laser power on the cladding can effectively be reduced by the micro-nano structure of the high power optical fiber laser combiner. The tolerant power and bundling power of the optical fiber laser combiner can be raised to increase the output power of the optical laser.