An integrated mode converter and multiplexer (/demultiplexer) is disclosed, which combines a multimode interference coupler (100), at least one phase-shifter (200) and a symmetrical Y-junction (300). The dispersion of the multimode interference coupler (100) is engineered through subwavelength structures in order to achieve a very wide bandwidth. Several phase-shifter (200) topologies for further bandwidth enhancement are disclosed, as well as architectures for multiplexing a greater number of optical modes.

A device for coupling a first waveguide with a second waveguide, wherein the core of the second guide includes an end portion having at least a flat end wall rotated facing, and preferably, in contact with the core of the first guide, a flared part of convex shape extending the end wall by extending from the first guide, the flared part having a section which increases by extending from the first guide, a narrowing, a main portion, extending the end portion by extending from the first guide and having a substantially constant section.

Systems and methods for non-hermetic Semiconductor Optical Amplifier (SOA) integration on a Silicon photonic (SiP) chip using Complementary Metal-Oxide-Semiconductor (CMOS) processes include creating a trench for placement of the SOA, wherein the trench is between two Spot Size Converters (SSCs) located on the SiP chip outside of the trench; forming pedestals in the trench in one or more existing CMOS layers of the SiP chip to guide vertical alignment of the SOA with the SSCs during its placement; and depositing metallic traces and a solder pattern in the trench above the pedestals to enable the SOAs to electrically bond and rest on the pedestals during reflow.

The present invention provides a photonic device such as a variable optical attenuator, in which two signal components, propagating in modes of two different polarization states, are converted to two different modes of the same polarization state prior to modulation. The modulation of both components is performed by a single device which applies the same modulation strength to both components. The two signal components can be converted back to propagate in the two different polarization states following modulation.

Systems and methods for non-hermetic Semiconductor Optical Amplifier (SOA) integration on a Silicon photonic (SiP) chip using Complementary Metal-Oxide-Semiconductor (CMOS) processes include creating a trench for placement of the SOA, wherein the trench is between two Spot Size Converters (SSCs) located on the SiP chip outside of the trench; forming pedestals in the trench in one or more existing CMOS layers of the SiP chip to guide vertical alignment of the SOA with the SSCs during its placement; and depositing metallic traces and a solder pattern in the trench above the pedestals to enable the SOAs to electrically bond and rest on the pedestals during reflow.

A spot-size converter includes a first part of a waveguiding structure to couple to a first waveguide to receive light from or transmit light to the first waveguide in a first propagation mode, wherein the first part of the waveguiding structure has a lower waveguiding structure with a varying effective refractive index that decreases away from the first waveguide; and a second part of the waveguiding structure to couple to a second waveguide to transmit light to or receive light from the second waveguide in a second propagation mode, the second part of the waveguiding structure includes an upper waveguiding structure with a plurality of high-index elements arranged therein, an overlap region is between the first part and the second part, the first propagation mode progressively transforms into the second propagation mode in the overlap region.

A SOI bent taper structure is used as a mode convertor. By tuning the widths of the bent taper and the bend angles, almost lossless mode conversion is realized between TE0 and TE1 in a silicon waveguide. The simulated loss is <0.05 dB across C-band. This bent taper can be combined with bi-layer TM0-TE1 rotator to reach very high efficient TM0-TE0 polarization rotator. An ultra-compact (9 m) bi-layer TM0-TE1 taper based on particle swarm optimization is demonstrated. The entire TM0-TE0 rotator has a loss <0.25 dB and polarization extinction ratio >25 dB, worst-case across the C-band.

A method of forming a semiconductor device may include providing semiconductor substrate having a substrate top side and a dielectric layer along the substrate top side and forming a first mask layer over the dielectric layer. The method may include forming a lower cladding wall and an upper cladding wall via a first opening in the first mask layer. The method may also include forming a second mask layer over the dielectric layer and forming side cladding walls via second openings in the second mask layer. Various semiconductor devices having a buried waveguide in formed via the method are also disclosed.

An optical waveguide structure includes a substrate and a core structure disposed on the substrate. The substrate includes a first waveguide region, a second waveguide region, and a transition region between the first waveguide region and the second waveguide region. The core structure includes first core segments arranged in a first direction and a second direction crossing the first direction on the transition region. The core structure includes second core segments arranged in the first direction and the second direction on the second waveguide region. The first direction and the second direction are parallel to a top surface of the substrate.

An optical mode converter and method of fabricating the same from wafer including a double silicon-on-insulator layer structure. The method comprising: providing a first mask over a portion of a device layer of the DSOI layer structure; etching an unmasked portion of the device layer down to at least an upper buried oxide layer, to provide a cavity; etching a first isolation trench and a second isolation trench into a mode converter layer, the mode converter layer being: on an opposite side of the upper buried oxide layer to the device layer and between the upper buried oxide layer and a lower buried oxide layer, the lower buried oxide layer being above a substrate; wherein the first isolation trench and the second isolation trench define a tapered waveguide; filling the first isolation trench and the second isolation trench with an insulating material, so as to optically isolate the tapered waveguide from the remaining mode converter layer; and regrowing the etched region of the device layer.