A device for connection to an on-board multiplexed network of communication by multi-mode optical fibers for an aircraft, the device comprising a first optical component for modifying the spatial profile of a light beam, comprising a multi-mode optical input terminal configured to be connected to a first multi-mode optical fiber and single-mode optical output terminals, and a second optical component for modifying the spatial profile of a light beam, comprising single-mode optical input terminals and a multi-mode optical output terminal configured to be connected to a second multi-mode optical fiber. It further comprises an optical harness for switching and reassigning a transmission channel including single-mode optical inputs coupled to the single-mode optical output terminals of the first component, single-mode optical outputs coupled to the single-mode optical input terminals of the second optical component, and single-mode waveguides.

A curved light guide structure configured to guide a spectral region, includes: end faces disposed at two ends of the ring segment structure; a first main side extending between the end faces and a second main side opposite the first main side and extending between the end faces; at least a first pass region on the first main side, the first pass region being configured to receive and let pass an optical signal within the spectral region, the curved light guide structure being configured to guide the optical signal along an axial direction between the end faces; and at least a second pass region on the second main side that is configured to let pass and to emit at least part of the optical signal from the curved light guide structure.

A device for multi-plane conversion of a first light radiation having a conversion block comprising a plurality of optical parts and implementing a plurality of phase masks to apply a spatiofrequential phase shift for producing a second light radiationa predetermined transformation, known as a transformation with separable variables. The predetermined transformation may link N modes of index {i, j}.sub.k, 1<=k<=N, of a first used mode family with separable spatial variables (x,y) describing the first light radiation in a first transverse plane with n modes of the same index {i, j}.sub.k 1<=k<=N, of a second used mode family with separable spatial variables (x,y) describing the second light radiation at a second transverse plane. The N modes of the second mode family are not Hermite-Gaussian modes. The N modes of the first mode family are not arranged on the first transverse plane in the form of a triangle.

In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a plurality of radiation beams before the beams are coupled into an optical fiber.

Two-port optical retro-reflectors with high isolation and high return loss are described. Such retro-reflectors are designed to increase the number of optical filtering using one or more filters uniquely disposed to increase the isolation and return loss.

An optical tap includes a support with a first port facing a first ferrule supporting a first fiber along a first axis. A beamsplitter is connected to the support and intersected by the first axis. A second port is fastened to the support and facing a second ferrule supporting a second fiber along a second axis that intersects the beamsplitter. A third port is fastened to the support and facing a third ferrule supporting a third fiber along a third axis that intersects the beamsplitter, wherein the beamsplitter splits a first light signal from the first port to sends first and second portions of the first signal to the second and third ports, respectively. When the beamsplitter may optionally be configured as a polarizing element and include elements configured to rotate relative to each other to change a ratio of the first and second portions. The optical tap may optionally include a light intensity controlling device located in an optical path between the beamsplitter and at least one of the second or third ferrules. Optionally, a first collimating lens is configured to expand a first light beam that is substantially aligned with the first axis, and a second collimating lens is located between the beamsplitter and the second port, and configured to contract the second portion of the expanded first light beam to the second port.

A 33 multi-mode interference coupling device having a length L and a width W, a center input port between a pair of outer input ports, where each outer input port is displaced from the center input port by a distance W/3, and a center output port between a pair of outer output ports, where each outer output port is displaced from the center output port by a distance W/3, where the device is supports C.sub.bar, C.sub.cen, and a C.sub.x coupling coefficients therein, when the outer input ports are equally excited with an input signal having a 180 phase difference, C.sub.cen from each outer input port destructively interferes when the propagation length L is an integer number of L.sub./2, where the device outputs equal intensity laser modes from each outer output port when the propagation length is an integer multiple of L.sub./2.

A light divider includes a light guide having a first surface and a second surface that reflect light incident on the light guide, the light guide causing the light to propagate through a portion between the first surface and the second surface, light dividing films that are provided in the light guide and so characterized that the light dividing films not only reflect but also transmit the light, and a plurality of light extracting portions that are provided on the first surface and allow light fluxes that the light dividing films have transmitted to exit through the first surface.

In one embodiment, an optical splitter/coupler may be created by i) providing an optical waveguide having a first waveguide channel core, ii) forming an angular trench at an end of the first waveguide channel core, the angular trench establishing first and second facets within the first waveguide channel core, and iii) mirroring the first and second facets, wherein the mirrored first and second facets are configured to provide optical reflection into and/or from respective second and third waveguide channel cores located at correspondingly opposing sides of the first waveguide channel core.

A non-intrusive monitoring optical connection apparatus includes first and second fiber optic communication lines (2, 8) arranged for light to pass therebetween. The first and second fiber optic communication lines (2, 8) have first and second ferrules (4, 6) at ends thereof, respectively. An optical element (13, 25) is disposed between the fiber optic communication lines (2, 8). Most of the light passes between the fiber optic communication lines (2, 8) and a small part of the light is harvested by the optical element (13, 25) and detected by a photo detector (15, 28).