Structures including an optical coupler and methods of fabricating a structure including an optical coupler. The structure includes a substrate, a first dielectric layer on the substrate, and an optical coupler having a first grating and a second grating. The first grating has a first plurality of segments positioned in a first level over the first dielectric layer. The second grating has a second plurality of segments positioned in a second level over the first dielectric layer. The second level differs in elevation above the first dielectric layer from the first level. The second plurality of segments are positioned in the second level to overlap with the first plurality of segments of the first grating, and the second plurality of segments comprise a metal. A second dielectric layer is positioned in a vertical direction between the first level and the second level.

An optical input polarization management device includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization so as to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Light within the first and second OW's is input to a first two-by-two optical splitter (2×2OS). A first phase shifter (PS) is interfaced with either the first or second OW. Light is output from the first 2×2OS into a third OW and a fourth OW. Light within the third and fourth OW's is input to a second 2×2OS. A second PS is interfaced with either the third or fourth OW. Light is output from the second 2×2OS into a fifth OW for further processing.

An optical device includes: a case; a sleeve attached to the case, the sleeve including a first through-hole penetrating between an inside and an outside of the case, and an inclined surface inclined with respect to a penetrating direction of the first through-hole, the inclined surface having an opening of the first through-hole; a first optical fiber including a core wire including a core and a clad, and a sheath configured to surround the core wire, wherein an exposed portion of the core wire not surrounded by the sheath passes through the first through-hole; and a first joining material interposed and sealed between an outer peripheral surface of the exposed portion and an inner peripheral surface of the first through-hole in the first through-hole.

An optical antenna may permit a duplex link formed by a transmit, Tx, beam towards a partner optical antenna and a receive, Rx, beam from the partner antenna. The antenna includes: a proximal path including a bidirectional waveguide for duplex propagation of the duplex link from a Tx source of the Tx beam and towards a receiver of the Rx beam; a distal path for a duplex propagation of the duplex link from/towards the partner optical antenna; a beam shaper positioned in the distal path to shape a duplex propagation pattern of the duplex link; and a controller controlling the beam shaper to adaptively shape the propagation pattern to enclose: a first position of the partner antenna at the transmission of the Rx beam; and a second of the partner antenna at the reception of the Tx beam.

A waveguide is provided. The waveguide includes a substrate having two outer surfaces for propagating a beam of light in the substrate by reflecting the beam from the two outer surfaces. The waveguide includes at least one polarization volume hologram (PVH) grating to couple light in and/or out of the waveguide. The PVH grating may be a multi-layer PVH grating with graded birefringence.

Technologies for optical coupling to photonic integrated circuit (PIC) dies are disclosed. In one illustrative embodiment, a PIC die has one or more waveguides and one or more vertical couplers to reflect light from the waveguides through a surface of the PIC die. An optical connector interface is positioned on the surface of the PIC die with high precision. The optical connector interface includes one or more lenses to collimate light from the one or more waveguides. An optical connector is plugged into the optical connector interface. The optical connector includes one or more lenses to focus the collimated light to one or more optical fibers. As the optical connector is coupling to collimated light, it does not need to be positioned with high precision.

A simple, compact and low-cost passive optical transceiver device with four terminals may be used in an optical transmission system with polarization-diversity coherent detection scheme. The transceiver is composed of a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. The device simultaneously operates as a transmitter and a receiver with optical signals propagating along opposite directions wherein non-reciprocal polarization rotation leads to distinct effects. The received optical signal is thus split into two orthogonal polarization components directed towards two separate ports.

An optical coupling device can include a first birefringent layer having opposing first and second surfaces. The first birefringent layer can split incident light received at the first surface into first and second beams. The first and second beams can have respective polarization orientations that are orthogonal to each other. The first birefringent layer can propagate the first and second beams along respective first and second paths within the first birefringent layer to the second surface. The first and second beams can be spatially separated at the second surface. A redirection layer facing the second surface of the first birefringent layer can include first and second grating couplers configured to respectively redirect the first and second beams to propagate within the redirection layer as respective third and fourth beams. In some examples, the third and fourth beams can have respective polarization orientations that are parallel to each other.

Provided is a connector assembly for optically connecting one or more optical fibers and an array of vertical coupling elements of a photonic integrated circuit (PIC). In various embodiments, the connector assembly is constructed to independently optically scale some feature sizes, such as, for example, the transverse mode size, the array size, the array geometry, and/or various incidence angles, the optical scaling being performed, e.g., from a fiber end face plane to a connector-mating plane and further to a PIC coupling plane. In some embodiments, the connector assembly may support a polarization (de)multiplexing functionality.

An optical coupling device can couple incident light from a fiber into waveguides, but can reduce the coupling of return light from the waveguides into the fiber. A Faraday rotator layer can rotate by forty-five degrees, with a first handedness, respective planes of polarization of incident beams, and can rotate by forty-five degrees, with a second handedness opposite the first handedness, respective planes of polarization of return beams. A redirection layer can include at least one grating coupler that can redirect an incident beam of one polarization so that the redirected path extends within the redirection layer toward a first waveguide, and can redirect an incident beam of an opposite polarization so that the redirected path extends within the redirection layer toward a second waveguide. An optional birefringent layer can spatially separate incident beam having different polarizations, so that two single-polarization grating couplers can be used.