Abstract: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

Abstract: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

Abstract: Described are optical devices and related methods wherein a multiple mode input in a Higher Order Mode (an HOM) optical fiber is converted by a complex mode transformer to produce a fundamental mode output in an optical medium with an E-field that is substantially different than that exiting the HOM optical fiber. The medium is preferably a Large Mode Area (LMA) optical fiber, or free space. The mode transformer may be a series of refractive index perturbations created either by photo-induced gratings or by gratings formed by physical deformations of the optical fiber.

Abstract: The specification describes a method for selectively depositing carbon nanotubes on the end face of an optical fiber. The end face of the optical fiber is exposed to a dispersion of carbon nanotubes while light is propagated through the optical fiber. Carbon nanotubes deposit selectively on the light emitting core of the optical fiber.

Abstract: This invention provides for an off-the-record e-mail system that can ensure that messages, particularly sensitive messages, are available only for the intended recipient and never reside on permanent storage media. Control of the existence of the off-the-record e-mail can lie completely with the sender. The sender of the off-the-record e-mail sets the time-to-live (TTL) for the message content. When an off-the-record e-mail message is deleted, there is preferably no trace of the e-mail message on any computer backup system. The sender may also update the e-mail content at any time. The off-the-record e-mail system can include a personal server that combines the functions of a web server and an e-mail transfer server. The personal server may reside on an individual's personal workstation and might serve no one but that particular user. The personal server acts as a broker between the sender and the sender's SMTP server.

Abstract: The output modal content of optical fibers that contain more than one spatial mode may be analyzed and quantified by measuring interference between co-propagating modes in the optical fiber. By spatially resolving the interference, an image of the spatial beat pattern between two modes may be constructed, thereby providing information about the modes supported by the optical fiber. Measurements of the phase front exiting the optical fiber under test are advantageously performed in the far field.

Abstract: Adverse hydrogen aging limitations in multiply-doped optical fibers are overcome by passivating these optical fibers using a deuterium passivation process. This treatment essentially pre-reacts the glass with deuterium so that the most active glass sites are no longer available to react with hydrogen in service. Optical fibers of main interest are doped with mixtures of germanium and phosphorus. Optimum passivating process conditions are described.

Abstract: A network method for using a network telephone voice-mail service, by which a caller may leave a voice-message that includes the identification of an attachment, which may include, as examples only, audio, video, text, programs, spreadsheets and graphic attachments. A video, text, spreadsheet or graphic attachment may be converted to an audible attachment to the voice-mail at the caller's or the voice-mail subscriber's request. Such entries may be made, after receiving an automated prompt for leaving an attachment identifier or conversion request, audibly or by using a keypad entry. A network method is also provided for using a network telephone voice-mail service, by which the voice-mail service may detect an attachment to a voice-mail message and provide access to the attachment to the voice-mail message.

Abstract: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

Abstract: The specification describes an improved approach to suppressing fast transients in optical amplifier systems. The approach relies on operating the amplifier in an automatic power-mode control with an extra loss component. It is applicable to optical amplifiers based on rare earth amplifier media, such as erbium doped fiber amplifiers (EDFAs).

Abstract: The specification describes methods for the manufacture of very large optical fiber preforms wherein the core material is produced by MCVD. Previous limitations on preform size inherent in having the MCVD starting tube as part of the preform process are eliminated by removing the MCVD starting tube material from the collapsed MCVD rod by etching or mechanical grinding. Doped overcladding tubes are used to provide the outer segments of the refractive index profile thus making most effective use of the MCVD produced glass and allowing the production of significantly larger MCVD preforms than previously possible.

Abstract: The specification describes an integrated passive device (IPD) that is formed on a silicon substrate covered with an oxide layer. Unwanted accumulated charge at the silicon/oxide interface are rendered immobile by creating trapping centers in the silicon surface. The trapping centers are produced by a polysilicon layer interposed between the silicon substrate and the oxide layer.

Abstract: The specification describes the production of optical fibers and optical fiber preforms using Chemical Powder Deposition (CPD). In this process a slurry of silica powders and dopant powders in a liquid carrier is prepared and the inside surface of a silica glass starter tube is coated with the slurry, then dried. The coating is then consolidated and the tube collapsed as in the conventional MCVD process. Multiple coatings, and coatings with varying compositions, can be used to produce any desired profile. In an alternative embodiment, doped silica glass of the desired final composition is prepared, and then pulverized to form the powder for the slurry. In both embodiments, the use of powders of known composition in the slurry allows direct control over the final glass composition, as compared with conventional processes in which the composition in the final glass is indirectly controlled by control of the thermodynamics of a vapor phase reaction.

Abstract: The specification describes optical devices and related methods wherein an input mode is converted by multiple LPG mode transformers to produce an output with multiple predetermined modes.

Abstract: Described are multimode optical fibers in which the differential in the mode delay for higher order modes is reduced for bending insensitive MMF. The result is preservation of low differential mode delay and high bandwidth while low bend loss is achieved. The designs are based on choosing a combination of a core profile and a cladding structure with a negative trench positioned at a radius related to the core profile. A feature of the preferred embodiments is a core with a hybrid refractive index profile. The hybrid refractive index profile is essentially a combination of a standard alpha profile and a step profile at the outer edge of the alpha profile.

Abstract: A method and system that reduces the impact of packet loss on video data quality. Packet selection is performed by the method and system to selectively drop low priority packets so that the overall quality of the received video data may be improved. In one exemplary embodiment, the probability of higher priority layers being delivered on time is computed and a packet is transmitted only if this probability is greater than a given threshold h. In another exemplary embodiment, the system and method have the capability of backing up the process to transmit previously skipped packets, if time allows.

Abstract: A method and system that reduces the impact of packet loss on video data quality. Packet selection is performed by the method and system to selectively drop low priority packets so that the overall quality of the received video data may be improved. In one exemplary embodiment, the probability of higher priority layers being delivered on time is computed and a packet is transmitted only if this probability is greater than a given threshold h. In another exemplary embodiment, the system and method have the capability of backing up the process to transmit previously skipped packets, if time allows.

Abstract: The output modal content of optical fibers that contain more than one spatial mode may be analyzed and quantified by measuring interference between co-propagating modes in the optical fiber. By spatially resolving the interference, an image of the spatial beat pattern between two modes may be constructed, thereby providing information about the modes supported by the optical fiber.

Abstract: The specification describes a thin film Integrated Passive Device (IPD) design that achieves isolation between conductive runners by shielding the top and bottom regions of a noisy runner with metal shield plates. The shield plates are derived from metal interconnect layers. The invention can be implemented by merely modifying the mask pattern for the metal interconnect layers. No added elements or steps are needed to fabricate the IPDs. The invention is suitable for use in Multi-Chip Modules (MCMs) or other arrangements where digital circuits and RF circuits are in close proximity.

Abstract: A method for fabricating an optical device wherein the device comprises a first substrate wafer with at least one buried optical waveguide on an approximately flat planar surface of the substrate and a second substrate wafer with at least a second buried optical waveguide. The waveguides so formed may be straight or curved along the surface of the wafer or curved by burying the waveguide at varying depth along its length. The second wafer is turned (flipped) and bonded to the first wafer in such a manner that the waveguides, for example, may form an optical coupler or may cross over one another and be in proximate relationship along a region of each. As a result, three-dimensional optical devices are formed avoiding the convention techniques of layering on a single substrate wafer.