A device and system for coupling optical vortex multiplexed light into and out of a photonic integrated circuit. The multi-mode forked grating coupler device comprises: (i) a multi-mode forked grating structure configured to receive at least one optical vortex multiplexed light beam, wherein the multi-mode forked grating structure comprises at least one forked region positioned amidst a plurality of grooves, wherein the forked region comprises a single groove forking into two grooves, wherein the single groove is noncontiguous with the two grooves, and wherein the plurality of grooves comprise a central bending region; (ii) an optical waveguide; and (iii) a tapered portion connecting the forked grating structure and the multi-mode optical bus waveguide.

The invention relates to an optoelectronic device for generation of a frequency comb comprising: a laser source (2); an optical micro-resonator (3), comprising a resonant ring (20); at least one waveguide (30) optically coupled to the resonant ring (20), having an effective index associated with a fundamental optical mode supported by the filtering guide (30) equal to an effective index associated with an optical higher order mode supported by the resonant ring (20).

In order to solve the problem of making optical signals pass at a low loss and low polarization dependence, this optical circuit element is configured from rib-type optical waveguides, each of which is configured from a core region, including a planar slab and protruding ribs, and cladding regions that are provided in contact with the top and the bottom of the core region. A first optical waveguide that is provided in the optical circuit element is provided with a plurality of intersection points where the first optical waveguide intersects optical waveguides other than the first optical waveguide, said intersection points being disposed on one straight line. The core width of the first optical waveguide in a region between the intersection points is larger than the core width of the first optical waveguide in regions other than the region between the intersection points, the first optical waveguide regions having different core widths are connected by means of a taper optical waveguide wherein the core width monotonously changes, and the thickness of the slab of the first optical waveguide in the region having the large core width is larger than the thickness of the slab of the first optical waveguide in the regions other than the region having the large core width.

A device and system for coupling optical vortex multiplexed light into and out of a photonic integrated circuit. The multi-mode forked grating coupler device comprises: (i) a multi-mode forked grating structure configured to receive at least one optical vortex multiplexed light beam, wherein the multi-mode forked grating structure comprises at least one forked region positioned amidst a plurality of grooves, wherein the forked region comprises a single groove forking into two grooves, wherein the single groove is noncontiguous with the two grooves, and wherein the plurality of grooves comprise a central bending region; (ii) an optical waveguide; and (iii) a tapered portion connecting the forked grating structure and the multi-mode optical bus waveguide

According to various embodiments, there is provided an optical device including: a waveguide configured to propagate an electromagnetic wave, the waveguide including a first grating and further including a second grating; a first further waveguide including a first further grating, the first further waveguide having a first width, wherein the first further grating is coupled to the first grating to form a first pair of coupled gratings, wherein a grating period of the first further grating is at least substantially equal to a grating period of the first grating; a second further waveguide including a second further grating, the second further waveguide having a second width, wherein the second further grating is coupled to the second grating to form a second pair of coupled gratings, wherein a grating period of the second further grating is at least substantially equal to a grating period of the second grating.

A sensing cable includes a first optical fiber, a second optical fiber that extends along the first optical fiber and that is spaced from the first optical fiber, and a transmitting material that includes an intervention portion present between the first optical fiber and the second optical fiber, the transmitting material being configured to transmit light from the first optical fiber to the second optical fiber through the intervention portion.

Optical waveguiding part (300), which waveguiding part is arranged to convey light through an output facet (30) of the waveguiding part, which waveguiding part comprises a ridge waveguide comprising a semiconductor substrate (320) and a semiconductor light-conveying ridge, wherein the output facet is set at an angle () in relation to a main direction (z) of light along the said waveguide, so that light travelling in the waveguide along said main direction has an angle of incidence towards the facet of between 2 and 14 and is reflected towards a first side (301) of the said ridge, wherein the waveguide comprises an MMI (Multi Mode Interferometer) (310), arranged to create an output image substantially at the output facet.

An amplification optical fiber operable to propagate light beams in a plurality of modes in a predetermined wavelength range through a core doped with a rare earth element, wherein Expression (1) is satisfied, where a cutoff wavelength of a propagated highest mode light beam is defined as max, under conditions in which the cutoff wavelength of the highest mode light beam is defined as c, a shortest wavelength of the wavelength range is defined as min, and a cutoff wavelength of a second-highest mode light beam to the highest mode light beam is min.
c>0.5 min+0.5 max(1).

An embodiment of the invention relates to a BI-MMF with OH group concentrations controlled along a radial direction. In the BI-MMF, an OH group concentration distribution along the radial direction has a shape in which a concentration peak is located in a concentration control interval provided between an outer periphery of a core and a trench part, including an interface between the core and trench part.

A photonic integrated circuit as discussed herein may include one or more multimode waveguide interfaces that define a corresponding transition between a waveguide and a free propagation region of a photonic integrated circuit. Specifically, a multimode waveguide interface may include an input waveguide that is connected to an interferometric waveguide, and a slab waveguide connected to the interferometric waveguide. The input waveguide and interferometric waveguide are positioned and configured to convert a portion of a first mode of light into a second mode of light, such that the first and second modes interfere within the interferometric waveguide. The interferometric waveguide is configured such that these modes are in phase for a first target wavelength and out of phase for a second target wavelength at an interface between the interferometric waveguide and the slab waveguide.