Abstract: A method for fabricating a micromachined optical mechanical modulator based WDM transmitter/receiver module is described. The Fabry-Perot cavity of the mechanical modulator is structured from a three-polysilicon-layer stack formed on the surface of a single crystalline silicon substrate. The polysilicon membrane and its supporting polysilicon beams of the cavity are cut from the top polysilicon layer of the stack and are released by selective etching of their underlying polysilicon. The etched underlying polysilicon layer is heavily doped and then converted into porous polysilicon by anodization in HF solution. The polysilicon membrane and its supporting polysilicon are finally released using a reactive ion etch process to avoid stiction often generated in a wet etch process. A conic hole is formed on the backside of the single crystalline silicon substrate for receiving an optical fiber that can be passively aligned with the Fabry-Perot cavity.

Abstract: A micromachined vertical vibrating gyroscope consists of three single crystal silicon assemblies: an outer single crystal silicon assembly, an intermediate single crystal silicon assembly, and an inner single crystal silicon assembly. The outer assembly includes a plurality of arc-shaped anchors arranged in a circle and extending from a single crystal silicon substrate coated with an insulating annulus thereon. The intermediate assembly is a suspended wheel concentric with the arc-shaped anchors. The inner assembly is a suspended hub concentric with the circle formed by the anchors and having no axle at its center. The three assemblies are connected to each other through several flexures. The intermediate suspended wheel is driven into rotational vibration by lateral comb capacitors. Input angular rates are measured by two vertical capacitors.

Abstract: Self-assembled photonic crystals, including large sphere planar opals, infiltrated planar opals and inverted planar opals, as well as methods for manufacturing same are provided. Large sphere planar opals are manufactured according to a method comprising the steps of: synthesizing monodisperse silica spheres, wherein each of the silica spheres has a diameter greater than or equal to about 400 nanometers; purifying the silica spheres; and self-assembling the silica spheres into a plurality of ordered, planar layers on a substrate. Infiltrated planar opals may also be manufactured by further processing the large sphere planar opal by sintering the planar opal and infiltrating the planar opal with a predetermined material. Inverted planar opals may further be manufactured by removing the silica spheres from the infiltrated planar opal. Various modifications to the substrate and planar opal are also provided to enhance the properties of these photonic crystals.

Abstract: A microbolometer infrared sensor utilizes a porous silicon bridge as its thermal isolating and mechanical supporting structure. Porous silicon formed from single crystal silicon on lightly doped p-type silicon has a thermal conductivity lower than silicon dioxide and silicon nitride, and, therefore, when used as a mechanical supporting structure, can offer better thermal isolation performance. The porous silicon layer can be fabricated much thicker than silicon dioxide and silicon nitride membranes since there is almost no residual stress therein. A thicker porous silicon bridge has higher mechanical support strength. The porous silicon process is a low temperature process. It facilitates a fabrication strategy of microelectronics first and micromechanics last.

Abstract: A wavelength division multiplexing transmitter and receiver module utilizes a micromachined silicon substrate as the mounting platform for its optical components and optoelectronic devices including an optical fiber, a transmitter, two receivers, and three microlenses. The micromachined silicon substrate has a V-groove for placing an optical fiber so that it is aligned with the mounted transmitter and the mounted receivers passively and has more V-grooves with slanted end side walls and opposite vertical end side walls used to form a dielectric multilayered filter, a half-mirror, and two anti-reflectors thereon which are eventually incorporated to be a multiplexer and/or a demultiplexer. The microlenses are disposed on V-supports. The transmitter is pre-mounted mounted on a V-submount. The microlens and the transmitter are then mounted into the V-grooves of the micromachined silicon substrate and aligned with the mounted optical fiber passively.

Abstract: Fiber optic interferometric sensors and methods of manufacturing same are disclosed. These sensors comprise a unitary substrate having a channel therein and an axis extending through the channel. The unitary substrate also comprises a reflective surface extending in a plane perpendicular to the axis. An optical fiber having a terminated surface thereon is also provided. The optical fiber extends axially within the channel and is arranged so that the terminated surface and the reflective surface are movable relative to one another in response to a phenomenon to be sensed. The unitary substrate also comprises positioning means integral therewith for positioning the optical fiber within the channel. The method of manufacturing the fiber optic interferometric sensors comprise the steps of providing a unitary substrate and forming a channel therein so that an axis extends therethrough.

Abstract: A silicon accelerometer comprising a substrate, one or more pairs of beams, a pedestal, a mass on top of the pedestal and a cavity beneath the pedestal all of which is formed by a single-sided processing method. The pedestal is suspended over the cavity by the beams which provides the only support for the pedestal. The beams are supported by the substrate. The main steps of fabricating this structure comprise diffusion or ion implantation and epitaxial growth to form a buried high donor concentration layer on the surface of the substrate, chemical vapor deposition and photoetching to expose a portion of the edge of the buried layer to the ambiente, anodization to convert the high donor concentration layer into porous silicon and selectively etching to remove the porous silicon.

Abstract: A silicon diaphragm piezoresistive pressure sensor having a diaphragm formed by a single-sided fabrication method. The pressure sensor is made up of a substrate on which there is a diaphragm at or near the surface of the substrate with a chamber under the diaphragm. The pressure sensor is fabricated by undercutting a silicon substrate to form a diaphragm and a cavity within the bulk of the substrate under the diaphragm. The fabricating steps including a) forming a buried low resistive layer under a predetermined diaphragm region; b) converting the low resistance layer into porous silicon by anodization of silicon in a concentrated hydrofluoric acid solution; c) removing the porous silicon by selective etching; d) filling the openings formed in the etching of porous silicon with a deposited material to form a sealed reference chamber. Adding appropriate means to the exterior of the diaphragm and substrate to detect changes in pressure between the reference chamber and the surface of the substrate.