Abstract: An invention pertaining to the measurement of the freezing point of substances using OCDR and OCT.technology.

Abstract: An invention pertaining to the measurement of the freezing point of substances using OCDR and OCT.technology.

Abstract: A network including a control channel source node and a plurality of control channel destination nodes is interconnected by communications media in the form of a ring. The control and control channel destination nodes transfer information over a plurality of channels using wavelength-division multiplex techniques. The control channel source node transmits control information to all of the control channel destination nodes over a unitary control channel, and each of the control channel destination nodes drains off a portion of the energy of the signal comprising the control channel to facilitate decoding and processing of the control information contained therein. Each of the aspects, the control channel destination nodes can also generate status information for transfer to the control channel source node over the control channel. The control channel source node drains off the energy of the signal comprising the control channel to facilitate decoding and processing of the status information contained therein.

Abstract: An imaging system for performing optical coherence tomography includes an optical radiation source; a reference optical reflector; a first optical path leading to the reference optical reflector; and a second optical path coupled to an endoscopic unit. The endoscopic unit preferably includes an elongated housing defining a bore; a rotatable single mode optical fiber having a proximal end and a distal end positioned within and extending the length of the bore of the elongated housing; and an optical system coupled to the distal end of the rotatable single mode optical fiber, positioned to transmit the optical radiation from the single mode optical fiber to the structure and to transmit reflected optical radiation from the structure to the single mode optical fiber.

Abstract: An imaging system for performing forward scanning imaging for application to therapeutic and diagnostic devises used in medical procedures. The imaging system includes forward directed optical coherence tomography (OCT), and non-retroreflected forward scanning OCT. Also interferometric imaging and ranging techniques and fluorescent, Raman, two-photon, and diffuse wave imaging can be used. The forward scanning mechanisms include a cam attached to a motor, pneumatic devices, a pivoting device, piezoelectric transducers, electrostatic driven slides for substantially transverse scanning; counter-rotating prisms, and offset lenses are used for arbitrary scanning. The imaging system of the invention is applied to hand held probes including probes integrated with surgical probes, scalpels, scissors, forceps and biopsy instruments. Hand held probes include forward scanning lasers.

Abstract: An auto-calibrating companion bit successive approximation system uses sampling and balancing capacitors in a charge redistribution digital-to-analog converter having multi-valued capacitors of magnitudes enabling redundant expression of electric charge values. Companion bits are used with sets of balancing capacitors for successive approximation of sampling voltages. A charge redistribution digital-to-analog converter has a sampling and balancing capacitors including associated companion bit capacitors represented by digital weights which are saved in memory. A non-binary weighted set of capacitors provides redundancy in a charge redistribution digital-to-analog converter employed in a successive approximation register architecture.

Abstract: An optical node for providing transport and switch functions on an incoming optical signal with a plurality wavelengths each with a plurality of signal components in a WDM optical network. The optical node includes a first module for taking, extracting and processing the plurality of wavelengths, a second module with a plurality of input ports and a plurality of output ports which further extract the signal components from the plurality of wavelengths, and a third module for taking and processing the signal components and sending them to the plurality of output ports in the second module. A method of processing the wavelengths in one of the nodes first inputs the optical signal that extracts wavelengths from the optical signal, and further extracts signal components from the wavelengths, to allocate signal components onto the input ports. Finally the method switches the signal components from the input ports to the output ports of the optical node.

Abstract: A Dense Wavelength Division Multiplexed (DWDM) optical transmission system that compensates for unequal channel performance over an extended fiber transmission distance.

Abstract: Ultra-small optical probes comprising a single-mode optical fiber and a lens which has substantially the same diameter as the optical fiber. The optical fiber and lens are positioned in a probe housing which is in the form of an insertional medical device such as a guidewire. Connector elements are provided to facilitate the attachment of the probe to an optical system and the quick disconnection of the probe from the optical system. The probe is used to obtain optical measurements in situ in the body of an organism and can be used to guide interventional procedures by a surgeon.

Abstract: An interface for coupling a modem port with a transmission line includes a hybrid converter having a variable gain amplifier coupling a transmit path of a first differential polarity and a received path of a second differential polarity.

Abstract: Data transmission apparatus includes first and second optical transmitters coupled to an optical link. A forward error correction (FEC) coder is coupled to the input of the second optical transmitter. A first information signal having a first information rate is provided to the first optical transmitter, and a second information signal having a second information rate is provided to the second optical transmitter. The use of the FEC coder enables the second information signal to have a higher information rate than the first information signal, while simultaneously enabling the respective output power levels of the first and second optical amplifiers to be substantially equal. The data transmission apparatus achieves higher data transmission capacity while retaining compatibility with pre-existing fiber spans and amplifier nodes.

Abstract: Multiple gigabit Ethernet (GbE) and Fiber Channel (FC) signals are multiplexed and transported on a wavelength-division multiplexed (WDM) communications link using synchronous optical network (SONET) signaling. A transmitter decodes the 8b/10b encoded GbE/FC signals to reduce their respective signaling rates to no greater than the payload data rate of an OC-48 signal used on the link. The decoded signal are packetized into fixed-size packets in order to append a stream identifier used for de-multiplexing at the receive end. The packetized streams are multiplexed together and formatted into the OC-48 signal, which is transmitted over the communications link. A receiver de-multiplexes the received signal to obtain the packet streams, converts the packet streams to the corresponding decoded signals, and re-encodes each signal to re-create the original GbE/FC signals. A pair of interfaces can be arranged to provide independent adding or dropping of the GbE/FC signals that share the same wavelength.

Abstract: A digital calibration system for an analog-to-digital converter system includes a computational system receiving digital bits from an analog-to-digital converter representing selection of elements of the digital-to-analog converter in response to an analog input. The computational engine produces a digital output representative of the analog input during conversion operation, and digital values for adjustment of an adjustable analog source during calibration. Further, a digital system comprises a radix-less-than-two non-configurable digital-to-analog converter, a comparator system connected to the converter, and a computational system configured for SAR calibration and conversion.

Abstract: A digital calibration system for an analog-to-digital converter system includes a computational system receiving digital bits from an analog-to-digital converter representing selection of elements of the digital-to-analog converter in response to an analog input. The computational engine produces a digital output representative of the analog input during conversion operation, and digital values for adjustment of an adjustable analog source during calibration. Further, a digital system comprises a radix-less-than-two non-configurable digital-to-analog converter, a comparator system connected to the converter, and a computational system configured for SAR calibration and conversion.

Abstract: A digital calibration system for an analog-to-digital converter system includes a computational system receiving digital bits from an analog-to-digital converter representing selection of elements of the digital-to-analog converter in response to an analog input. The computational engine produces a digital output representative of the analog input during conversion operation, and digital values for adjustment of an adjustable analog source during calibration. Further, a digital system comprises a radix-less-than-two non-configurable digital-to-analog converter, a comparator system connected to the converter, and a computational system configured for SAR calibration and conversion.

Abstract: An apparatus for measuring the optical-signal-to-noise ratio (OSNR) of an optical system is adapted to function in single channel or in multi-channel wavelength division multiplexed optical communication systems. An optical signal spectrum and a center frequency characterize the optical signals. A narrow-band notch filter, realized by an in-fiber Bragg grating, is utilized to remove a component of the signal so the remaining signal can be measured. When multiple channels are present, a bandpass filter is used to select the part of the multiplexed signal to be measured. Both the narrow-band notch filter and the bandpass filter can be tunable to further extend the capabilities of the system. Two detectors are utilized with the power in the channel being measured by a low-gain detector and the power in the noise being measured by a high-gain detector. A processor receives the detector outputs, calculates OSNR, and controls the tunable components.

Abstract: A time domain data converter with output frequency domain conversion. A data conversion circuit is operable to receive a signal in the time domain and provide an output in the frequency domain. It includes a data converter for converting data from an analog format to a digital format in the time domain. It also includes a processor for processing the data in the digital format output from the data converter through a time domain/frequency domain transform to provide data in the digital format in the frequency domain. The output of the frequency domain operation or the time domain operation can be provided for output in response to the generation of a data ready signal.

Abstract: A digital calibration system for an analog-to-digital converter system includes a computational system receiving digital bits from an analog-to-digital converter representing selection of elements of the digital-to-analog converter in response to an analog input. The computational engine produces a digital output representative of the analog input during conversion operation, and digital values for adjustment of an adjustable analog source during calibration. Further, a digital system comprises a radix-less-than-two non-configurable digital-to-analog converter, a comparator system connected to the converter, and a computational system configured for SAR calibration and conversion.

Abstract: A Dense Wavelength Division Multiplexed (DWDM) optical transmission system that compensates for unequal channel performance over an extended fiber transmission distance.

Abstract: A multistage comparator is calibrated to remove quasi-autozero voltages derived from the native comparator offset and autozero switch charge injection offsets. A multistage comparator includes a plurality of series connected amplifiers each having a programmable source, and further including a latch. A calibration method for a multistage comparator includes calibrating the first of a series of amplifiers first for both voltage offset and charge injection errors thereby to remove the quasi-autozero voltage and charge injection offsets.