The semiconductor device includes an optical waveguide WG1 formed in a planar manner, and a three-dimensional optical waveguide WG2 optically connected with the optical waveguide WG1 and including a curved shape.

The disclosed embodiments generally relate to extruding multiple layers of micro- to nano-polymer layers in a tubular shape. In particular, the aspects of the disclosed embodiments are directed to a method for producing a Bragg reflector comprising co-extrusion of micro- to nano-polymer layers in a tubular shape.

The present disclosure provides a few mode optical fiber (100). The few mode optical fiber (100) includes a core region (102). A core region (102) defined by a region around a central longitudinal axis (116) of the few mode optical fiber (100). In addition, the core region (102) has a first annular region (106) extended from central longitudinal axis (116) to radius r.sub.1, a second annular region (108) extended from radius r.sub.1 to radius r.sub.2, a third annular region (110) extended from radius r.sub.2 to radius r.sub.3, a fourth annular region (112) extended from radius r.sub.3 to radius r.sub.4 and a fifth annular region (114) extended from radius r.sub.4 to radius r.sub.5. Also, the few mode optical fiber (100) has a cladding defined by the sixth annular region (104) extended from radius r.sub.5 to radius r.sub.6.

The refractive index of a fiber core of a few mode optical fiber is n1. A cladding layer surrounding the fiber core includes: a downward-concave cladding layer surrounding the fiber core, the refractive index thereof is n2; a first upward-convex cladding layer surrounding the downward-concave cladding layer, the refractive index thereof is n3; a second upward-convex cladding layer surrounding the first upward-convex cladding layer, the refractive index thereof is n4; an outer layer surrounding the second upward-convex cladding layer, the refractive index thereof is n5. The refractive indexes of the fiber core, the downward-concave cladding layer, the first upward-convex cladding layer, the second upward-convex cladding layer, the outer layer satisfy: n.sub.1>n3>n.sub.4>n.sub.5>n.sub.2. The fiber is a non-single mode in a direct waveguide state, and equivalent single-mode transmission can be achieved when the optical fiber is bent at a specific bending radius.

Provided is a few-mode optical fiber. The optical fiber includes: a core and a cladding enclosing the core. The cladding includes: a first inner cladding surrounding the core; a first high-refractive-index mode filter layer surrounding the first inner cladding; a second inner cladding surrounding the first high-refractive-index mode filter layer; a second high-refractive-index mode filter layer surrounding the second inner cladding; and an outer cladding surrounding the second high-refractive-index mode filter layer.

Disclosed herein are methods, apparatus, and systems for perturbing an optical beam propagating within a first length of fiber to adjust one or more beam characteristics of the optical beam in the first length of fiber or a second length of fiber or a combination thereof, coupling the perturbed optical beam into a second length of fiber and maintaining at least a portion of one or more adjusted beam characteristics within a second length of fiber having.

Disclosed herein are methods, apparatus, and systems for providing an optical beam delivery system, comprising an optical fiber including a first length of fiber comprising a first RIP formed to enable, at least in part, modification of one or more beam characteristics of an optical beam by a perturbation assembly arranged to modify the one or more beam characteristics, the perturbation assembly coupled to the first length of fiber or integral with the first length of fiber, or a combination thereof and a second length of fiber coupled to the first length of fiber and having a second RIP formed to preserve at least a portion of the one or more beam characteristics of the optical beam modified by the perturbation assembly within one or more first confinement regions. The optical beam delivery system may include an optical system coupled to the second length of fiber including one or more free-space optics configured to receive and transmit an optical beam comprising the modified one or more beam characteristics.

An optical fiber for converting a Gaussian laser beam into a Bessel laser beam may include a first segment optically coupled to a second segment with a transition region, the first segment having a first outer diameter greater than a second outer diameter of the second segment. The first segment may include a first core portion with a first cladding portion extending around the first core portion. The first core portion may have an annular core region with a relative refractive index relative to the first cladding portion. The second segment may include a second core portion with a second cladding portion extending around the second core portion. The second core portion has a relative refractive index relative to the second cladding portion and the relative refractive index of the first annular core region may be substantially equal to the relative refractive index of the second core portion.

A differential mode attenuation compensator includes a first multi-mode optical fiber and a third multi-mode optical fiber in which a plurality of propagation modes propagate in a wavelength of a propagating optical signal; and a second multi-mode optical fiber including a core and a clad and arranged with a central axis aligned between the first multi-mode optical fiber and the third multi-mode optical fiber, in which each loss in the plurality of propagation modes is different in the first multi-mode optical fiber and the third multi-mode optical fiber.

Provided is a few-mode optical fiber. The optical fiber includes: a core and a cladding enclosing the core. The cladding includes: a first inner cladding surrounding the core; a first high-refractive-index mode filter layer surrounding the first inner cladding; a second inner cladding surrounding the first high-refractive-index mode filter layer; a second high-refractive-index mode filter layer surrounding the second inner cladding; and an outer cladding surrounding the second high-refractive-index mode filter layer.