Abstract: Designs, methods, and applications for fault localization and fiber security in optical transponders is described. In one embodiment a two-way time transfer protocol or other suitable method for synchronizing clocks between distant transponders is used. The clock synchronized transponders have digital signal processing to continually detect high precision time-histories of physical layer attributes in the transmission between the two transponders. Physical layer attributes can include: state-of-polarization changes, changes in polarization-mode-dispersion, change in propagation delay, changes or loss-of-light, changes in OSNR, changes in BER between the two nodes. By recording these physical layer changes and time-stamping them information on the magnitude and estimated location of the changes can be inferred by from the time records. In one aspect the method may be used in a distributed optical sensor for monitoring trespassing events that are a risk to fiber security of an optical transmission link.

Abstract: Systems, devices and methods of producing an image are provided. A electro-magnetic radiation source provides electro-magnetic radiation to a sample and a reference. A detector/interferogram unit produces at least one interferogram that is supplied to a signal processing unit. The signal processing unit extracts phase, magnitude, and/or polarization data from the supplied signals, and produces an image based on at least the extracted data.

Abstract: Designs, methods, and applications for fault localization and fiber security in optical transponders is described. In one embodiment a two-way time transfer protocol or other suitable method for synchronizing clocks between distant transponders is used. The clock synchronized transponders have digital signal processing to continually detect high precision time-histories of physical layer attributes in the transmission between the two transponders. Physical layer attributes can include: state-of-polarization changes, changes in polarization-mode-dispersion, change in propagation delay, changes or loss-of-light, changes in OSNR, changes in BER between the two nodes. By recording these physical layer changes and time-stamping them information on the magnitude and estimated location of the changes can be inferred by from the time records. In one aspect the method may be used in a distributed optical sensor for monitoring trespassing events that are a risk to fiber security of an optical transmission link.

Abstract: Systems, devices and methods of producing an image are provided. A electro-magnetic radiation source provides electro-magnetic radiation to a sample and a reference. A detector/interferogram unit produces at least one interferogram that is supplied to a signal processing unit. The signal processing unit extracts phase, magnitude, and/or polarization data from the supplied signals, and produces an image based on at least the extracted data.

Abstract: Optical probes having a diameter less than substantially 500 ?m for use in scanning light from a long, highly flexible fiber to a sample. In one embodiment the probe includes a viscous damping fluid suitable to prevent non-uniform rotational distortion (NURD).

Abstract: Optical probes having a diameter less than substantially 500 &mgr;m for use in scanning light from a long, highly flexible fiber to a sample. In one embodiment the probe includes a viscous damping fluid suitable to prevent non-uniform rotational distortion (NURD).

Abstract: A method and apparatus for in-circuit biasing of a modulated laser and bit error rate testing of an optical transmitter and/or optical receiver under the control of a test controller. The test controller is communicably coupled to an interface of a module under test, as well as to external test equipment. The test controller modifies operational parameters of the modulated laser, in order to obtain a desired output power and to obtain a predetermined extinction ratio. The operational parameters of the laser include a laser bias current, an electro-absorption modulator offset bias current and a modulation depth. The disclosed test controller also determines whether the optical transmitter and/or receiver exhibit acceptable bit error rates. The disclosed test controller uses a variable optical attenuator, in combination with an erbium-doped fiber amplifier (EDFA) to control an optical signal to noise ratio for a signal terminating at either the transmitter or the receiver of the optical transceiver under test.

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

Abstract: An imaging system wherein an optical signal is transmitted to both a sample to be measured and a rotating element which is calibrated to the system. A return signal is detected by the system, and a scan analyzer and correction unit uses the system calibration information along with synchronization information to correct for return signal degradation or errors due to imperfections in the rotating element in real time. This allows for an accurate measurement of the sample. The system can also include a coarse path-length adjustment unit to allow the system to track a region of interest within a sample to further allow for accurate sample measurement.

Abstract: Method of performing OFDR on a sample comprising steps of: providing an external-cavity frequency-tuned laser having an optical cavity of effective length; tuning the laser to generate a change in wavelength; changing the effective length of the optical cavity proportionally to the change in wavelength so as to tune the longitudinal cavity mode frequency at the same rate as the wavelength is changed; directing light from the laser onto the sample; receiving light reflected from the sample; combining light reflected from the sample with light from the external-cavity frequency-tuned laser; detecting the combined light and generating a beat signal in response thereto; and performing digital signal processing to extract spatial information about the sample in response to the detected beat signal.

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 optical system, in one embodiment including an external-cavity frequency-tuned laser having a tunable longitudinal cavity mode and a center tunable wavelength. The external-cavity frequency-tuned laser includes an optical cavity, an optical gain medium positioned within the optical cavity, and a rapid tuning wavelength selecting device positioned to receive light from the optical gain medium and adapted to return selected wavelengths of light to the optical gain medium. The external-cavity frequency-tuned laser is substantially continuously tunable and the tunable wavelength selecting device tunes the center wavelength of the external-cavity frequency-tuned laser at the same rate as the longitudinal cavity mode of the external-cavity frequency-tuned laser is tuned. In another embodiment the optical system includes an interferometer in optical communication with the external-cavity frequency-tuned laser.