Abstract: Methods are disclosed of fabricating an optical assembly. An active optical element is disposed near or on a first surface of a slab of optical material. A passive optical element is formed on a second surface of the slab, with the second surface being substantially parallel to the first surface. An optical axis of the passive optical element is aligned with an optical path between the passive optical element and an active region of the active optical element using a lithographic alignment process.

Abstract: Methods and structures are disclosed demultiplexing optical signals transmitted over an optical fiber into a silicon substrate and to multiple detectors. The silicon substrate has two spaced-apart surfaces and a diffractive element disposed adjacent to one of the surfaces. Each of the optical signals corresponds to one of multiple wavelengths. The optical signals are directed into the silicon substrate along a path through the first surface to be incident on the diffractive element. The path is oriented generally normal with the first surface and/or with the diffractive element, which angularly separates the optical signals such that each of the wavelengths traverses through the substrate in a wavelength dependent direction to the first surface. Each optical signal is steered from the first surface towards the second surface to be incident on different optical elements that direct them generally normal to the first surface to be incident on one of the detectors.

Abstract: Methods of forming a 3D structure in a substrate are disclosed. A layer of resist is deposited on the substrate. The layer of resist is patterned to define an edge at a predetermined location. The resist is reflowed to form a tapered region extending from the etch. Both the reflowed resist and the substrate are concurrently etched to transfer the tapered profile of the reflowed resist into the underlying substrate to form an angled surface. The etching is discontinued before all of the resist is consumed by the etching.

Abstract: A semiconductor laser having an optical volume of between about 0.1×?3 to about 30×?3, where ? is the wavelength of light emitted by the semiconductor laser. The semiconductor laser comprises an optical cavity having a proximal and distal end; a first reflector disposed at the proximal end; a second reflector disposed at the distal end, said optical cavity being defined by the first and second reflectors; an active region disposed transversely with respect to the optical cavity, wherein the semiconductor laser produces an axial emission of light from the distal end of the optical cavity.

Abstract: A waveguide is provided including a first photon propagating material having a first index of refraction (n1) and having a pinch disposed therein, the pinch having a second index of refraction (n1?); and a second photon propagating material disposed in optical communication with the first photon propagating material and having a third index of refraction (n2); wherein n1<n1, n1?<n2, and the pinch redirects at least a portion of the photons from the first photon propagating material to the second photon propagating material.

Abstract: A method of fabricating on a substrate an optical detector in an optical waveguide, the method involving: forming at least one layer on a surface of the substrate, said at least one layer comprising SiGe; implanting an impurity into the at least one layer over a first area to form a detector region for the optical detector; etching into the at least one layer in a first region and a second region to form a ridge between the first and second regions, said ridge defining the optical detector and the optical waveguide; filling the first and second regions with a dielectric material having a lower refractive index than SiGe; and after filling the first and second regions with the dielectric material, removing surface material to form a planarized upper surface.

Abstract: A method of fabricating a detector that involves: forming a trench in a substrate, the substrate having an upper surface; forming a first doped semiconductor layer on the substrate and in the trench; forming a second semiconductor layer on the first doped semiconductor layer and extending into the trench, the second semiconductor layer having a conductivity that is less than the conductivity of the first doped semiconductor layer; forming a third doped semiconductor layer on the second semiconductor layer and extending into the trench; removing portions of the first, second and third layers that are above a plane defined by the surface of the substrate to produce an upper, substantially planar surface and expose an upper end of the first doped semiconductor layer in the trench; forming a first electrical contact to the first semiconductor doped layer; and forming a second electrical contact to the third semiconductor doped layer.

Abstract: An optoelectronic circuit including: an IC chip made up of a substrate in which an optical waveguide and a mirror have been fabricated, the substrate having a first lens formed thereon, wherein the mirror is aligned with the optical waveguide and the first lens is aligned with the mirror to form an optical path connecting the first lens, the mirror, and the optical waveguide; and an optical coupler including a second lens, the optical coupler affixed to the substrate and positioned to align the second lens with the first lens so as to couple an optical signal into or out of the optical waveguide within the IC chip.

Abstract: A planar integrated circuit includes a semiconductor substrate having a substrate surface and a trench in the substrate, a waveguide medium in the trench having a top surface and a light propagation axis, the trench having a sufficient depth for the waveguide medium to be at or below said substrate surface, and at least one Schottky barrier electrode formed on the top surface of said waveguide medium and defining a Schottky barrier detector consisting of the electrode and the portion of the waveguide medium underlying the Schottky barrier electrode, at least the underlying portion of the waveguide medium being a semiconductor and defining an electrode-semiconductor interface parallel to the light propagation axis so that light of a predetermined wavelength from said waveguide medium propagates along the interface as a plasmon-polariton wave.

Abstract: A method of fabricating a detector that involves: forming a trench in a substrate, the substrate having an upper surface; forming a first doped semiconductor layer on the substrate and in the trench; forming a second semiconductor layer on the first doped semiconductor layer and extending into the trench, the second semiconductor layer having a conductivity that is less than the conductivity of the first doped semiconductor layer; forming a third doped semiconductor layer on the second semiconductor layer and extending into the trench; removing portions of the first, second and third layers that are above a plane defined by the surface of the substrate to produce an upper, substantially planar surface and expose an upper end of the first doped semiconductor layer in the trench; forming a first electrical contact to the first semiconductor doped layer; and forming a second electrical contact to the third semiconductor doped layer.

Abstract: A method of fabricating a waveguide mirror that involves etching a trench in a silicon substrate; depositing a film (e.g. silicon dioxide) over the surface of the silicon substrate and into the trench; ion etching the film to remove at least some of the deposited silicon dioxide and to leave a facet of film in inside corners of the trench; depositing a layer of SiGe over the substrate to fill up the trench; and planarizing the deposited SiGe to remove the SiGe from above the level of the trench.

Abstract: A circuit for generating a clock or sampling signal, the circuit including: a semiconductor quantum dot laser element including a region of quantum dots, wherein the region of quantum dots is characterized by an emission distribution having a half-width of at least about 10 meV; and drive circuitry connected to the quantum dot laser element for operating the quantum dot laser element as a mode-locked laser that outputs a periodic, uniformly spaced sequence of pulses, wherein the clock or sampling signal is derived from the sequence of pulses.