Abstract: In accordance with the invention, increased maximum modulation speeds and improved hole distribution are obtained for light emitting devices. Barrier layers of a quantum well structure for a light emitting device are formed with varying barrier energy heights. Quantum well layers of the quantum well structure are formed between the barrier layers.

Abstract: Methods and devices to measure threshold voltages of MEMS devices are disclosed. The threshold voltages are based on test voltages which cause the devices to change states. State changes of the device are detected by monitoring integrated current or charge used to drive the test voltages.

Abstract: Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.

Abstract: Methods are described for selecting reflective layer distances in an interferometric modulator display that result in reduced color sensitivity to temperature and process variation. Colors are selected for interferometric modulator subpixels that correspond to a minimum in the rate that the colors change with respect to reflective layer distance. In some cases, colors are selected that deviate from the minimums in order to obtain a desired target color (e.g., a desired white point).

Abstract: Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.

Abstract: Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.

Abstract: Charge balanced display data writing methods use write and hold cycles of opposite polarity during selected frame update periods. Spatial dithering of hold cycle signals can reduce flicker.

Abstract: In accordance with the invention, increased maximum modulation speeds and improved hole distribution are obtained for light emitting devices. Barrier layers of a quantum well structure for a light emitting device are formed with varying barrier energy heights. Quantum well layers of the quantum well structure are formed between the barrier layers.

Abstract: In one embodiment, there is disclosed a waveguide medium using total internal reflection to create a relatively sharp (approximately 90°) bend for optical signals traversing the waveguide. A discontinuity of the medium (such as air) is used to create a turning mirror within the waveguide path. By curving the discontinuity, the entire input optical signal is focused into the output portion of the waveguide, thereby compensating for the diffraction loss of the optical signal at the bend. In one embodiment in order to facilitate proper alignment of the masks certain portions of the waveguide on a first mask are extended (widened) beyond their optimum physical size. This extended portion is then used to position an edge of a second mask, such that optical signal scatter caused by the extended portions of the waveguide are compensated for by adjusting the curvature.

Abstract: Embodiments of the invention involve a monolithic vertical configuration for coupling a ring resonator and a bus waveguides. The monolithic vertical coupling arrangement, with the epitaxial grown coupling between the waveguide and the resonator, provides control of the coupling coefficient. The vertical coupling arrangement allows for different material compositions in the waveguide and resonator structures, e.g. active quantum well resonators and transparent waveguides, to facilitate the design of active WDM components.

Abstract: A light modulator having a waveguide and a resonator is disclosed. The waveguide routes light of wavelength ? past the resonator. The resonator is coupled to the waveguide such that a portion of the light is input to the resonator, the resonator having a resonance at ?. The resonator includes a gain region in which light of wavelength ? is amplified and an absorption region in which light of wavelength ? is absorbed, the absorption region having first and second states, the first state absorbing less light of wavelength ? than the second state, the state of the absorption region is determined by an electrical signal coupled to the absorption region. The gain region provides a gain that compensates for the light absorption in the first state. In one embodiment, the waveguide and resonator are critically coupled when the absorption region is in the second state.

Abstract: A modulator having a waveguide and a microdisk resonator is disclosed. The waveguide has an input port for receiving a light signal of wavelength ? and an output port for transmitting modulated light. The microdisk resonator has a resonance at ? and is coupled to the waveguide between the input and output ports such that at least 10 percent of the light traveling in the waveguide is coupled to the microdisk resonator. The microdisk resonator further includes a material having a first state and a second state, the material absorbing more of the light in the first state than in the second state. The first and second states are selectable by a signal that is applied to the microdisk resonator. In one embodiment, the waveguide and the microdisk resonator occupy different portions of a sheet of material having the various layers used to construct the resonator.

Abstract: A modulator having a waveguide and a microdisk resonator is disclosed. The waveguide has an input port for receiving a light signal of wavelength ? and an output port for transmitting modulated light. The microdisk resonator has a resonance at ? and is coupled to the waveguide between the input and output ports such that at least 10 percent of the light traveling in the waveguide is coupled to the microdisk resonator. The microdisk resonator further includes a material having a first state and a second state, the material absorbing more of the light in the first state than in the second state. The first and second states are selectable by a signal that is applied to the microdisk resonator. In one embodiment, the waveguide and the microdisk resonator occupy different portions of a sheet of material having the various layers used to construct the resonator.