Fiber-optic communication systems form the high-capacity transport infrastructure that enables global broadband data services and advanced Internet applications. The desire for higher per-fiber transport capacities and, at the same time, the drive for lower costs per end-to-end transmitted information bit has led to optically routed networks with high spectral efficiencies. Among other enabling technologies, advanced optical modulation formats have become key to the design of modern wavelength division multiplexed (WDM) fiber systems. In this paper, we review optical modulation formats in the broader context of optically routed WDM networks. We discuss the generation and detection of multigigabit/s intensity- and phase-modulated formats, and highlight their resilience to key impairments found in optical networking, such as optical amplifier noise, multipath interference, chromatic dispersion, polarization-mode dispersion, WDM crosstalk, concatenated optical filtering, and fiber nonlinearity

Advanced Optical Modulation Formats

Multi-objective meta-heuristics: An overview of the current state-of-the-art

A mobile entertainment and communication device in a palm-held size housing has a cellular or satellite telephone capable of wireless communication with the Internet and one or more replaceable memory card sockets for receiving a blank memory card for recording data directly from the Internet and, in particular, musical performances that then can be selectively reproduced by the device for the enjoyment of the user, including both audio and visual recordings and reproductions. The device also includes a camera and microphone for recording images and sound within the range of the device that can be wirelessly transmitted, either selectively or automatically to a remote telephone. Further, the device includes sensors for sensing unusual conditions that may also be transmitted to a remote telephone, together with the location of the device as determined by a GPS section of the device.

Mobile Entertainment and Communication Device

A software and/or hardware facility that enables users to associate annotations with text segments contained in digital content. A capture client allows users to create annotations associated with text segments on content being viewed by the user. The annotations are stored in association with the text segments by an annotation server. When a user subsequently views content, text fragments in the viewed content are compared with the stored text segments by the facility. Text segments that are found to match the text fragments are identified by the facility, and the associated annotations displayed to the user on the viewed content by a display client. Because stored annotations are associated with a text segment, rather than the original content or an identifier associated with the original content from which the text segment was identified, annotations are able to be applied to any content that utilizes the text segment in the future.

Capture and display of annotations in paper and electronic documents

A system and method for automatically providing content associated with captured information is described. In some examples, the system receives input by a user, and automatically provides content or links to content associated with the input. In some examples, the system receives input via text entry or by capturing text from a rendered document, such as a printed document, an object, an audio stream, and so on.

Automatically providing content associated with captured information, such as information captured in real-time

This paper presents a 90-nm CMOS 10-Gb/s transceiver for chip-to-chip communications. To mitigate the effects of channel loss and other impairments, a 5-tap decision feedback equalizer (DFE) is included in the receiver and a 4-tap baud-spaced feed-forward equalizer (FFE) in the transmitter. This combination of DFE and FFE permits error-free NRZ signaling over channels with losses exceeding 30 dB. Low jitter clocks for the transmitter and receiver are supplied by a PLL with LC VCO. Operation at 10-Gb/s with good power efficiency is achieved by using half-rate architectures in both transmitter and receiver. With the transmitter producing an output signal of 1200mVppd, one transmitter/receiver pair and one PLL consume 300mW. Design enhancements of a half-rate DFE employing one tap of speculative feedback and four taps of dynamic feedback allow its loop timing requirements to be met. Serial link experiments with a variety of test channels demonstrate the effectiveness of the FFE/DFE equalization

A 10-Gb/s 5-Tap DFE/4-Tap FFE Transceiver in 90-nm CMOS Technology

Disclosed is a circuit for performing correlated double sampling entirely in the digital domain. In an exemplary embodiment, the circuit includes a plurality of comparators, each having a first input coupled to an associated data line for receiving first and second signals in first and second sampling intervals, respectively. A time varying reference signal is applied to the second input of each comparator. A plurality of up/down counters are coupled to respective ones of the comparators, and each is operable to count in a first direction during the first sampling interval and in an opposite direction during the second sampling interval. Each up/down counter is caused to stop counting when the amplitude of the variable reference signal substantially equals the amplitude of the respective first or second signal. As a result, each up/down counter provides an output representing a subtraction of one of said first or second signals from the other. The invention has particular utility when used in conjunction with a CMOS image sensor.

Correlated double sampling with up/down counter

Intersymbol interference (ISI) caused by intermodal dispersion in multimode fibers is the major limiting factor in the achievable data rate or transmission distance in high-speed multimode fiber-optic links for local area networks applications. Compared with optical-domain and other electrical-domain dispersion compensation methods, equalization with transversal filters based on distributed circuit techniques presents a cost-effective and low-power solution. The design of integrated distributed transversal equalizers is described in detail with focus on delay lines and gain stages. This seven-tap distributed transversal equalizer prototype has been implemented in a commercial 0.18-/spl mu/m SiGe BiCMOS process for 10-Gb/s multimode fiber-optic links. A seven-tap distributed transversal equalizer reduces the ISI of a 10-Gb/s signal after 800 m of 50-/spl mu/m multimode fiber from 5 to 1.38 dB, and improves the bit-error rate from about 10/sup -5/ to less than 10/sup -12/.

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Integrated transversal equalizers in high-speed fiber-optic systems

A parallel, 32-channel, high density (140 /spl mu/m pitch), 500 Mb/s NRZ, point-to-point, optical data link has been fabricated using existing GaAs IC, silicon optical bench (SiOB), and multichip module (MCM-D) technologies. The main components of the transmitter and the receiver modules are a GaAs-based vertical cavity surface emitting laser (VCSEL) array at 850 mn with its IC driver array chip and an integrated metal-semiconductor-metal (MSM) receiver (photodetector and signal processing circuits) array at 850 nm. The package module uses a modified 164 I/O JEDEC premolded plastic quad flat pack (PQFP) in combination with a polymer film integrated circuit (POLYFIC) chip carrier. The electrical input and output are 500 Mb/s NRZ binary signals. The optical I/O in both modules consists of a directly-connectorized (nonpigtail) fiber array block that plugs into the 32/spl times/1 optical fiber ribbon directly on one side and accepts 32 optical signals from the SEL array or delivers them to the MSM receiver array via a gold-coated 45/spl deg/ polished fiber array mirror. The MACII-32 ribbon cable is an enhanced version of the standard MACII connector ribbon cable. This paper characterizes key components of the optical data link, describes its package design, and discusses preliminary component and optical data link test results. >

Technology development of a high-density 32-channel 16-Gb/s optical data link for optical interconnection applications for the optoelectronic technology consortium (OETC)

In an illustrative embodiment, an instant camera is provided which includes an imager for receiving an image of an object to be photographed. The imager outputs a signal corresponding to the received image, and a memory device stores the signal. A printer prints instant film photographs corresponding to received or stored images, and has the capability to print at least one image on a single piece of instant film. A preview unit has at least one display for displaying an image corresponding to a received or stored image. A controller, in communication with the imager, the memory device, the printer, and the preview unit, controls the transfer of the signal from the imager to the memory device, from the memory device to the printer, and from the memory device to the preview unit.

S. Gowda

Papers

A 10-Gb/s 5-Tap DFE/4-Tap FFE Transceiver in 90-nm CMOS Technology

Correlated double sampling with up/down counter

Integrated transversal equalizers in high-speed fiber-optic systems

Technology development of a high-density 32-channel 16-Gb/s optical data link for optical interconnection applications for the optoelectronic technology consortium (OETC)

Digital instant camera having a printer