A III-V semiconductor waveguide nanoridge structure having a narrow supporting base with a freestanding wider body portion on top, is disclosed. In one aspect, the III-V waveguide includes a PIN diode. The waveguide comprises a III-V semiconductor waveguide core formed in the freestanding wider body portion; at least one heterojunction incorporated in the III-V semiconductor waveguide core; a bottom doped region of a first polarity positioned at a bottom of the narrow supporting base, forming a lower contact; and an upper doped region of a second polarity, forming an upper contact. The upper contact is positioned in at least one side wall of the freestanding wider body portion.

Provided is an infrared modulator including a silicon substrate, a multiple buffer layer on the silicon substrate, the multiple buffer layer including indium phosphide (InP), a first type semiconductor layer on the multiple buffer layer, the first type semiconductor layer including InP, a light absorption layer on the first type semiconductor layer, the light absorption layer including a quantum well structure including indium gallium arsenic phosphide (InGaAsP), and a second type semiconductor layer on the light absorption layer, the second type semiconductor layer including InP.

A display screen includes: a display panel with a display region and a non-display region, wherein the display region includes an intermediate display region and a peripheral display region surrounding the intermediate display region; an image expansion structure disposed in the peripheral display region, wherein the image expansion structure is configured to expand an image displayed by the peripheral display region of the display panel to the non-display region to cover the non-display region.

Example embodiments relate to an electro-optical device that includes a vertical p-i-n diode waveguide. The electro-optical device includes a waveguide portion adapted for propagating a multimode wave, the waveguide portion including an intrinsic semiconductor region of the vertical p-i-n diode, a first contact and a second contact for electrically contacting a first electrode and a second electrode of the vertical p-i-n diode. The device also includes an input section for coupling radiation into the waveguide portion and an output section for coupling radiation out of the waveguide portion. The input section, the output section, and the waveguide portion are configured to support a multimode interference pattern for the multimode wave with an optical field with a lateral inhomogeneous spatial distribution in the waveguide portion including regions with higher optical field intensity and regions with lower optical field intensity. The second contact physically contacts the second electrode.

An electro-optical circuit in which diode-like electrical characteristics of an optical modulator employed therein are used to generate one or more DC-offset levels that place the optical modulator into a proper electrical operating configuration for modulating light transmitted therethrough. In an example embodiment, the optical modulator includes an optical waveguide comprising at least a portion of a semiconductor diode connected to a data driver using a clamping circuit, the clamping circuit being configured to cause a data-modulated electrical signal outputted by the data driver to set a DC-offset level applied to the semiconductor diode. As a result, the use of on-chip and/or on-board bias-tees can advantageously be avoided. In some embodiments, the optical modulator can be driven using two different data signals, each used to set a different respective DC-offset level at the semiconductor diode. In various embodiments, the optical modulator can be an intensity modulator and/or a phase modulator.

A device for guiding and absorbing electromagnetic radiation, the device including: absorbing means for absorbing the electromagnetic radiation; and a coupled to the absorbing means for guiding the electromagnetic radiation to the absorbing means, wherein the waveguide and the absorbing means are formed from a structure including a first cladding layer, a second cladding layer over the first cladding layer, and a quantum-well layer between the first and second cladding layers, the quantum-well layer being formed of a material having a different composition to the first and second cladding layers, wherein the thickness and the composition of the quantum-well layer is optimised to provide an acceptable level of absorption of electromagnetic radiation in the waveguide while providing an appropriate band gap for absorption of the electromagnetic radiation in the absorbing means.

An optical transmission apparatus includes a first multilevel optical phase modulator and a first semiconductor optical amplifier. The first semiconductor optical amplifier includes a first active region having a first multiple quantum well structure. Assuming that a first number of layers of a plurality of first well layers is defined as n.sub.1 and a first length of the first active region is defined as L.sub.1 (?m): (a) n.sub.1=5 and 400?L.sub.1?563; (b) n.sub.1=6 and 336?L.sub.1?470; (c) n.sub.1=7 and 280?L.sub.1?432; (d) n.sub.1=8 and 252?L.sub.1?397; (e) n.sub.1=9 and 224?L.sub.1?351; or (f) n.sub.1=10 and 200?L.sub.1?297.

An optoelectronic device. The device comprising: a multi-layered optically active stack, including one or more layers comprising a III-V semiconductor material; an input waveguide, arranged to guide light into the stack; and an output waveguide, arranged to guide light out of the stack. The multi-layered optically active stack is butt or edge coupled to the input waveguide and output waveguide.

A semiconductor optical apparatus is disclosed, wherein the semiconductor optical apparatus comprises a first waveguide region defining a first mode size and a second active waveguide region defining a second mode size being smaller than the first mode size. The second active waveguide region is optically coupled to the first waveguide region and the second active waveguide region comprises a lower multiple quantum well layer and an upper multiple quantum well layer located above the lower multiple quantum well layer. The lower multiple quantum well layer is physically separated from the upper multiple quantum well layer by a spacer layer. The upper multiple quantum well layer comprises a mode transformation region configured to reduce the size of an optical mode from the first mode size to the second mode size.

An optoelectronic device. The optoelectronic device operable to provide a PAM-N modulated output, the device comprising: M optical modulators, M being an integer greater than 1, the M optical modulators being arranged in a cascade, the device being configured to operate in N distinct transmittance states, as a PAM-N modulator, wherein, in each transmittance state of the N distinct transmittance states, each of the M optical modulators has applied to it a respective control voltage equal to one of: a first voltage or a second voltage. One or more of the modulators may include a substrate; a crystalline cladding layer, on top of the substrate; and an optically active region, above the crystalline cladding layer. The crystalline cladding layer may have a refractive index which is less than a refractive index of the optically active region.