Abstract: The semiconductor laser has a resonance cavity composed of a gain chip, a Mach-Zehnder wide tuning port, and a wavelength-selective mirror component formed either as a ring resonator or a reflective Fabry-Perot etalon. Optical signals generated by the gain chip propagate through the wide tuning port and into the wavelength-selective mirror component and are then reflected back to the gain chip. The wavelength-selective mirror component is configured to reflect only those optical signals having wavelengths within a set of sharp peaks so that the laser cavity resonates only within the sharp peaks. The wavelength-selective mirror component is heated to adjust internal dimensions to maintain one of the sharp peaks at a selected emission wavelength. As optical signals pass through the wide tuning port, the signals are split between two channels of differing lengths resulting in optical interference.

Abstract: A total temperature probe with a complimentary sensor cavity for measuring multiple properties of a fluid flowing rapidly through the probe. The probe includes a sensor housing for diverting a portion of the rapidly flowing fluid into a primary flow path. A sample chamber within the probe houses a total temperature probe and is configured to divert a portion of the rapidly flowing fluid from a primary flowpath. An ancillary chamber adjacent to the sample chamber is configured to house an additional sensor and to divert a portion of the rapidly flowing fluid from the sample chamber. In some embodiments, the ancillary chamber diverts fluid directly from the rapidly flowing fluid. Preferably, the sensor housed within the ancillary chamber measures the water vapor level within the rapidly flowing fluid.

Abstract: The method and system operate to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM) and to lock the laser to a selected transmission wavelength. In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a set of transmission lines for detection by a detector. Another portion of the beam is routed directly to another detector. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line.

Abstract: The method and apparatus operates to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM). In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. The WTL is tuned to the ITU grid using an etalon and a gas cell having acetylene, hydrogen cyanide or carbon dioxide. Initially, the absolute transmission wavelengths of the WTL are calibrated by routing an output beam from the WTL through the etalon and through the gas cell while varying tuning parameters of the WTL to thereby generate an etalon spectrum and a gas absorption spectrum both as functions of the tuning parameters. The etalon and gas absorption spectra are compared, along with input reference information specifying gas absorption as a function of absolute wavelength, to determine the absolute transmission wavelength for the WTL as a function of the tuning parameters.

Abstract: A system and method is provided to calibrate a transmission laser, such as a widely tunable laser (WTL), within a dense wavelength division multiplexer (DWDM) for transmission through an optic fiber. The WTL is tuned to the ITU grid using an etalon and a gas cell. The absolute transmission wavelengths of the WTL are calibrated by routing a WTL output beam through the etalon and through the gas cell while varying tuning parameters of the WTL to generate an etalon spectrum and a gas absorption spectrum, both as functions of the tuning parameters. The etalon and gas absorption spectra are compared, along with input reference information specifying gas absorption as a function of absolute wavelength, to determine the absolute transmission wavelength for the WTL as a function of the tuning parameters. The WTL is then tuned to align the transmission wavelength of the WTL to an ITU transmission grid line.

Abstract: A chromatic dispersion characterization system for an optical transmission path is based on setting the operating point (the DC bias) of an external modulator alternatively on the inverting and non-inverting characteristic of the modulator. A dispersion regime of choice may be selected based on the modulator's alpha parameter, and the BER information recorded against the respective values of the DC bias. This system can be used to determine when the net CD in a link is zero, i.e. the network provider has provisioned sufficient compensation to match the CD in the link. The link operates in a zero-dispersion regime when the quality of the received signal does not change between the two modes.

Abstract: The architecture for a photonic transport network provides for separation of passthru channels form the drop channels at the input of a switching node. A wavelength switching sub-system then switches the passthru channels, without OEO conversion. The drop channels are directed to broadband receiver of choice using a broadcast and select drop tree. The add channels are inserted at the output side of the node, using tunable transponders. In addition, a passthru channel may be OEO converted if signal conditioning and/or wavelength conversion are necessary. The transponders, regenerators and transceivers are not wavelength specific, allowing flexible and scaleable network configurations. This structure provides for fast provisioning of new services and ‘class of service’ network recovery in case of faults.

Abstract: The method and system operate to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM) and to lock the laser to a selected transmission wavelength. In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a set of transmission lines for detection by a detector. Another portion of the beam is routed directly to another detector. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line.

Abstract: The method and system operate to maintain a widely tunable laser (WTL) at a selected transmission wavelength. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a transmission line for detection by an etalon fringe detector. Another portion of the beam is routed directly to a laser wavelength detector to determine the power of the beam. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line. The wavelength-locking controller thereafter monitors the temperature of the etalon and keeps the temperature constant to prevent any wavelength drift attributable to the etalon.

Abstract: The semiconductor laser has a resonance cavity composed of a gain chip, a Mach-Zehnder wide tuning port, and a wavelength-selective mirror component formed either as a ring resonator or a reflective Fabry-Perot etalon. Optical signals generated by the gain chip propagate through the wide tuning port and into the wavelength-selective mirror component and are then reflected back to the gain chip. The wavelength-selective mirror component is configured to reflect only those optical signals having wavelengths within a set of sharp peaks so that the laser cavity resonates only within the sharp peaks. The wavelength-selective mirror component is heated to adjust internal dimensions to maintain one of the sharp peaks at a selected emission wavelength. As optical signals pass through the wide tuning port, the signals are split between two channels of differing lengths resulting in optical interference.

Abstract: A semiconductor laser is provided having a cavity including a gain chip, a Mach-Zehnder wide tuning port, and a ring resonator mirror. Optical signals generated by the gain chip propagate through the Mach-Zehnder wide tuning port and into the ring resonator mirror where the optical signals are reflected back through the Mach-Zehnder wide tuning port to the gain chip. The ring resonator is configured to reflect only those optical signals back into the laser cavity having wavelengths within a set of sharp peaks and the laser cavity therefore can resonate only within one of the sharp peaks. The ring resonator mirror is heated to adjust its dimensions so as to maintain one of the sharp peaks at a selected emission wavelength. As optical signals reflected from the ring resonator pass through the Mach-Zehnder wide tuning port, the signals are split between two channels of differing lengths resulting in optical interference.

Abstract: The method and system operate to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM) and to lock the laser to a selected transmission wavelength. In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a set of transmission lines for detection by a detector. Another portion of the beam is routed directly to another detector. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line.

Abstract: A system and method is provided to calibrate a transmission laser, such as a widely tunable laser (WTL), within a dense wavelength division multiplexer (DWDM) for transmission through an optic fiber. The WTL is tuned to the ITU grid using an etalon and a gas cell. The absolute transmission wavelengths of the WTL are calibrated by routing a WTL output beam through the etalon and through the gas cell while varying tuning parameters of the WTL to generate an etalon spectrum and a gas absorption spectrum, both as functions of the tuning parameters. The etalon and gas absorption spectra are compared, along with input reference information specifying gas absorption as a function of absolute wavelength, to determine the absolute transmission wavelength for the WTL as a function of the tuning parameters. The WTL is then tuned to align the transmission wavelength of the WTL to an ITU transmission grid line.

Abstract: The method and system operate to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM) and to lock the laser to a selected transmission wavelength. In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a set of transmission lines for detection by an etalon fringe detector. Another portion of the beam is routed directly to a laser wavelength detector. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line.

Abstract: The invention provides a method and system for transmitting very high bit rates over an optical link, using unidirectional and bidirectional WDM technology. The 1550 nm window for optical transmission is spatially separated into two bands, "Red" and "Blue", and the channels in each band are selected so that respective wavelengths present a substantially equal gain tilt. A fiber amplifier designed according to spatial separation and wavelength selection of the invention is disclosed, along with multiple span WDM network topologies.

Abstract: The invention provides a method and system for transmitting very high bit rates over an optical link, using unidirectional and bidirectional WDM technology. The 1550 nm window for optical transmission is spatially separated into two bands, "Red" and "Blue", and the channels in each band are selected so that respective wavelengths present a substantially equal gain tilt. A fiber amplifier designed according to spatial separation and wavelength selection of the invention is disclosed, along with multiple span WDM network topologies.

Abstract: The invention provides a method and system for transmitting very high bit rates over an optical link, using unidirectional and bidirectional WDM technology. The 1550 nm window for optical transmission is spatially separated into two bands, "Red" and "Blue", and the channels in each band are selected so that respective wavelengths present a substantially equal gain tilt. A fiber amplifier designed according to spatial separation and wavelength selection of the invention is disclosed, along with multiple span WDM network topologies.