The various methods and devices described herein relate to devices which, in at least certain embodiments, may include one or more sensors for providing data relating to user activity and at least one processor for causing the device to respond based on the user activity which was determined, at least in part, through the sensors. The response by the device may include a change of state of the device, and the response may be automatically performed after the user activity is determined.

Automated Response to and Sensing of User Activity in Portable Devices

An experimental technique is described for observing the effects of switching transients in digital MOS circuits that perturb analog circuits integrated on the same die by means of coupling through the substrate Various approaches to reducing substrate crosstalk (the use of physical separation of analog and digital circuits, guard rings, and a low-inductance substrate bias) are evaluated experimentally for a CMOS technology with a substrate comprising an epitaxial layer grown on a heavily doped bulk wafer Observations indicate that reducing the inductance in the substrate bias is the most effective Device simulations are used to show how crosstalk propagates via the heavily doped bulk and to predict the nature of substrate crosstalk in CMOS technologies integrated in uniform, lightly doped bulk substrates, showing that in such cases the substrate noise is highly dependent on layout geometry A method of including substrate effects in SPICE simulations for circuits fabricated on epitaxial, heavily doped substrates is developed >

Experimental Results and Modeling Techniques for Substrate Noise in Mixed-Signal Integrated Circuits

Peripherals and data processing systems are disclosed which can be configured to interact based upon sensor data. In one embodiment, a peripheral, which is configured to be used with a data processing system, includes an interface to couple the peripheral to the data processing system, and at least one sensor, such as a proximity sensor, to sense a user of the peripheral, and a processor coupled to the interface and to the at least one sensor, wherein the processor configures the peripheral in response to data from the at least one sensor. The peripheral may communicate sensor data from its sensors to the data processing system, which may be a wireless PDA, and the data processing system analyzes the sensor data from its sensors and from the peripheral's sensors to decide how to configure the peripheral and/or the data processing system based on the sensor.

Methods and systems for automatic configuration of peripherals

This paper is divided into two major parts. Following a brief introduction that establishes some definitions and assumptions, Section II updates our earlier study on the limits of the RF performance of optical links. Section III reviews progress since our 1997 review paper in the development of devices enabling link performance closer to these limits, including (but not limited to): 1) cascade lasers that permit broad-band direct modulation links with gain >0 dB; 2) injection-locked edge- and surface-emitting lasers at 1300 and 1550 nm with modulation frequency responses as great as 40 GHz; 3) modulators with improved performance, especially electroabsorption modulators that now have switching voltages as low as 0.36 V, or handle optical powers as great as 60 mW, or have bandwidths as great as 50 GHz (but not all three of these in one device yet); and 4) high-speed photodetectors with high saturation currents, e.g., a 20-GHz device with a saturation current of 90 mA and a 55-GHz device with saturation at 50 mA. We conclude in Section IV by summarizing the component developments necessary for higher performance RF-over-fiber links, i.e.: 1) semiconductor lasers (for direct modulation) that have higher slope efficiency and bandwidth and lower relative intensity noise (RIN) at reasonable bias current levels; 2) continuous wave (CW) lasers (for external modulation) with higher fiber-coupled power and lower RIN; 3) higher frequency lower loss external modulators with more linear transfer functions and lower V/sub /spl pi// that can withstand larger CW optical powers; and 4) photodetectors with higher responsivity and bandwidth that respond linearly even when illuminated by greater average optical powers.

Limits on the performance of RF-over-fiber links and their impact on device design

Apparatuses and methods to sense proximity and to detect light. In one embodiment, an apparatus includes an emitter of electromagnetic radiation and a detector of electromagnetic radiation; the detector has a sensor to detect electromagnetic radiation from the emitter when sensing proximity, and to detect electromagnetic radiation from a source other than the emitter when sensing visible light. The emitter may be disabled at least temporarily to allow the detector to detect electromagnetic radiation from a source other than the emitter, such as ambient light. In one implementation, the ambient light is measured by measuring infrared wavelengths. Also, a fence having a non-IR transmissive material disposed between the emitter and the detector to remove electromagnetic radiation emitted by the emitter. Other apparatuses and methods and data processing systems and machine readable media are also described.

Integrated proximity sensor and light sensor

In this letter, we demonstrate a high-performance evanescently coupled photodiode (ECPD) with the partially p-doped photoabsorption layer. As compared to the control ECPD with the traditional intrinsic photoabsorption layer, the demonstrated device can exhibit much higher output saturation current (power) and electrical bandwidth without sacrificing the quantum efficiency performance. By properly designing the geometry size and epilayer structures of the partially p-doped ECPD, very high responsivity (1.01 A/W), high electrical bandwidth (around 50 GHz), and high saturation current bandwidth product (920 mA/spl middot/GHz, at 40 GHz) have been achieved simultaneously at 1.55-/spl mu/m wavelength.

High-performance evanescently edge coupled photodiodes with partially p-doped photoabsorption layer at 1.55-/spl mu/m wavelength

An injection-locked frequency divider (ILFD) with variable division ratio, controlled by the input offset voltage, was realized using a 0.13 /spl mu/m CMOS technology. In this report, the controllable division ratios were made from 2 up to 16 with an input AC signal of 10 GHz, by changing the input DC offset voltages. This divider also performs division ratios of 2, 4, 6 and 8 with a wide-locking range up to 20 GHz at 2.5 GHz self-oscillation. The DC supplied voltage of this circuit is only 2 V and the dividing capability can reach 20 GHz.

20 GHz CMOS injection-locked frequency divider with variable division ratio

We demonstrate a novel p-i-n photodiode (PD) structure, the separated-transport-recombination PD, which can greatly relieve the tradeoffs among the resistance-capacitance bandwidth limitation, responsivity, and output saturation power performance. Incorporating a short carrier lifetime (less than 1 ps) epitaxial layer to serve as a recombination center, this device exhibits superior speed and power performance to a control PD that has a pure intrinsic photoabsorption layer. Our demonstrated structure can also eliminate the bandwidth degradation problem of the high-speed photodetector, whose active photoabsorption layer is fully composed of short lifetime (/spl sim/1 ps) materials, under high dc bias voltages.

https://ir.nctu.edu.tw:443/bitstream/11536/13447/1/000230799100046.pdf

Separated-transport-recombination p-i-n photodiode for high-speed and high-power performance

We demonstrate a novel structure of electroabsorption modulator (EAM) at a 1.55-/spl mu/m wavelength: the dual-depletion-region EAM. After an n/sup +/ delta-doped layer was inserted into the thick intrinsic region (550 nm) of a tradition p-i-n modulator, the tradeoff between driving-voltage and electrical bandwidth performance can be released effectively. This new structure can also release the burden imposed on downscaling the width or length of high-speed EAM with low driving-voltage performance. The microwave and electrical-to-optical measurement of this novel device with traveling-wave electrodes show very convincing results.

Demonstration of a dual-depletion-region electroabsorption modulator at 1.55-/spl mu/m wavelength for high-speed and low-driving-voltage performance

The present invention is an optical fiber system and method for carrying both CATV and Ethernet signals. The digital signals are translated into higher band by a direct up/down conversion so that analog signals and digital signals are treated as different frequency bands of electrical signals. Then, all the signals are mixed/divided by a power combiner/divider. And then, by using optoelectronic devices, the signals are processed with optoelectronic conversion. The converted optical signals are transmitted in a fiber or a related optical channel having low channel loss yet high capacity. To sum up, the present invention can transmit digital signals together with analog signals in a single wavelength to save the cost of an optical signal system and to provide a convenience on rearranging the system.

Fan-Hsiu Huang

Papers

High-performance evanescently edge coupled photodiodes with partially p-doped photoabsorption layer at 1.55-/spl mu/m wavelength

20 GHz CMOS injection-locked frequency divider with variable division ratio

Separated-transport-recombination p-i-n photodiode for high-speed and high-power performance

Demonstration of a dual-depletion-region electroabsorption modulator at 1.55-/spl mu/m wavelength for high-speed and low-driving-voltage performance

Optical fiber system and method for carrying both CATV and Ethernet signals