Abstract: A method for forming, and an arrangement for using arbitrary angle mirrors in substrates is disclosed. An erodible material, such as a photoresist, is applied to a substrate at a site and is exposed to radiation at that site which has a linear variation in energy at the surface of the erodible material. Due to this variation in exposure energy, a taper results in the erodible material after development. The tapered region is then etched in a manner which etches both the erodible layer and the underlying substrate. The taper in the erodible layer provides a varying attenuation during the etching process such that the taper of the erodible layer, or a multiple of it, is transferred to the substrate. In a first embodiment, a tapered reflective surface is formed in a substrate, which surface engages an optical signal and deflects it to an optical device or another surface.

Abstract: A device having an optical modulation region and a photodetection region formed on a single wafer, and methods for making the device, are disclosed. In one configuration, the device consists of an off-axis nonpolar substrate that has, on one side, a region suitable for modulating an optical signal. The other side of the substrate has a region suitable for photodetection. The region suitable for modulating an optical signal includes a movable layer suspended over the substrate. As the movable layer moves under an applied voltage, the reflectivity of the modulation region changes. The photodetection region consists of a plurality of III-V layers. In a second configuration, the device consists of a III-V substrate that has a region for photodetection disposed on one surface. A region for optical modulation is disposed on the photodetection region.

Abstract: Apparatus and methods for a combined optical modulator/photodetector are disclosed. A modulator chip is attached to a photodetector chip using a non-conductive epoxy or solder. The combined modulator/photodetector can be configured in at least two ways. In one configuration, the modulator is located on the upper surface of a chip that is attached, at its lower surface, to a photodetector containing chip. In another configuration, the modulator is located on the lower surface of the modulator chip, which is again attached at its lower surface to the pbotodetector chip. By combining the modulator and photodetector in the manner described above, they can be placed in a single package, resulting in reduced packaging costs versus a separately packaged modulator and a separately packaged photodetector. Moreover, feedback from the photodetector can used to optimize the operation of micromechanical optical modulators.

Abstract: A process for manufacturing precise alloy compositions in nonlinear alloy systems. The invention implements a new quadratic fitting function that relates alloy composition c.sub.A for a variable A to input fluxes f.sub.A and f.sub.B, as c.sub.A =f.sub.A.sup.2 /(f.sub.A.sup.2 +/.beta.f.sub.B.sup.2). .beta. is a parameter that is used to modify the incorporation of the Group V input variable B. This modification is necessary because of different surface populations of Group V dimer species. This new fitting function precisely predicts alloy compositions in nonlinear systems, such as the GaAs.sub.l-y P.sub.y system, where y is set equal to the composition c.sub.A.

Abstract: A method and apparatus for a micromechanical modulator having a reduced-mass multilayer membrane is disclosed. The modulator includes a movable composite membrane suspended over a subtrate. The composite membrane consists of an overlayer and an underlayer. The overlayer is characterized by a thickness that is less than one-quarter of a wavelength of the optical signal being modulated. Under the action of a bias voltage, the movable membrane moves from a quiescent position to a second position closer to the substrate. The modulator is fabricated so that in either the quiescent position or the second position the gap between the composite membrane and the substrate is equal to d=m.lambda./4-n.sub.s s when n.sub.u is about equal to (n.sub.s) .sup.0.5, where m is an even integer, .lambda. is the wavelength of the optical signal being modulated, n.sub.s is the refractive index of the subtrate, n.sub.u is the refractive index of the underlayer, n.sub.

Abstract: A method and apparatus are disclosed for an integrated photonic device. A transparent non-imaging optical director having a top and a bottom surface is integrated, at its bottom surface, with a photonic device. The bottom surface is approximately equal in area to the active area of the photonic device. The top surface of the director is larger than its bottom surface. The top and bottom surface are connected by a waveguiding region. The geometry and refractive index of the non-imaging optical director are controlled so that the light entering the director is preferably totally internally reflected. Substantially all optical energy of an optical signal received at the top surface of the non-imaging optical director will be directed to its bottom surface, and then to the integrated photonic device. Where the photonic device is an optical source, substantially all optical energy emitted that is received by the bottom surface is directed to the top surface.

Abstract: Nonpolar substrates comprising off-axis growth regions for the growth of polar semiconductors, and a method for making such substrates, are disclosed. According to the invention, an erodible material, such as a photoresist, is applied to a substrate at a site and is exposed to radiation at that site which has an linear variation in energy at the surface of the erodible material. Due to this variation in exposure energy, a taper results in the erodible material after development. The tapered region is then etched in a manner which etches both the erodible layer and the underlying substrate. The taper in the erodible layer provides a varying attenuation during the etching process such that the taper of the erodible layer is transferred to the substrate.

Abstract: A method and apparatus for modulating an optical signal, and a method for fabricating such an apparatus, are disclosed. The modulator comprises a membrane, which consists of at least three layers, and a substrate, spaced to form an air gap. The layers of the membrane are characterized by a relationship between the refractive indices of the layers and the refractive index of the substrate. The membrane is suspended in a first position over the substrate by a flexible support arrangement. A biasing force is applied to the membrane and the substrate to create an electrostatic force to move the membrane towards the substrate to a second position. The reflectivity of the device to an optical signal changes as the membrane moves from the first position to the second position, thereby modulating the signal.