Abstract: Provided is an apparatus for determining the temperature of at least one fluid. The apparatus includes an optical fiber. A first end of the optical fiber is connected to at least one fiber tip, and a first additional reflector is introduced into the at least one fiber tip at a first predetermined distance from an outer end of the at least one fiber tip. A second end of the optical fiber is connected to a processing apparatus. The processing apparatus includes an optical source. The optical source is configured to launch an optical signal into the optical fiber, and a coherent detector.

Abstract: The invention relates to a communication network comprising an Internet protocol (IP) network and an optical network, wherein the IP network defines an IP domain and comprises a plurality of IP network elements, wherein the optical network defines an optical domain and comprises a plurality of optical network elements and an optical network management system, which takes over control functions in the optical domain, and wherein at least one IP network element comprises at least one optical transceiver which is connected, via an optical path, to a dedicated optical network element.

Abstract: A solution is provided for processing optical signals, wherein a mixing signal and a transmission carrier are both derived from a single light source, and wherein the mixing signal is located within a frequency band of a received signal and/or wherein the transmission carrier is located within the frequency band of the transmission signal.

Abstract: Provided is a method for determining a required adaption of a bias of an electro-optic modulator. The electro-optic modulator includes an input waveguide that is split into two paths. The two paths are then recombined into an output waveguide. The method includes the steps of recording a modulation voltage applied to the electro-optic modulator over a particular amount of time; recording a power at an output of the electro-optic modulator in response to the modulation voltage over the particular amount of time; correlating the recorded modulation voltage and the recorded power; and determining the required adaption of the bias based on the correlation between the recorded modulation voltage and the recorded power.

Abstract: In a method for interrogating at least one optical sensor coupled to an optical path, at least two time-shifted optical signals are fed into the optical path and reflected optical signals of the at least two probe signals created by the at least one optical sensor are detected. Each detected reflected optical signal is assigned to one of the at least one optical sensor and a correct optical frequency is assigned to each detected reflected optical signal. An absolute value or a value range or a change of a value or value range of the parameter to be sensed is determined from the one or more of the following physical conditions: the optical reflection signals, the reflectivity of the at least one optical sensor, and the frequency of each detected optical reflection signal, or from one or more dependencies that link these physical conditions.

Abstract: Provided is an apparatus for determining the temperature of at least one fluid. The apparatus includes an optical fiber. A first end of the optical fiber is connected to at least one fiber tip, and a first additional reflector is introduced into the at least one fiber tip at a first predetermined distance from an outer end of the at least one fiber tip. A second end of the optical fiber is connected to a processing apparatus. The processing apparatus includes an optical source. The optical source is configured to launch an optical signal into the optical fiber, and a coherent detector.

Abstract: The present disclosure relates to an optical time domain reflectometry method including the steps of feeding a plurality of unipolar optical probe signals to a near end of an optical path under test, receiving a corresponding plurality of reflected unipolar optical receive signals, creating a corresponding plurality of digital receive data signals, calculating at least one correlation signal by correlating the digital receive data signals with a bit sequence corresponding to a respective probe bit sequence, and determining the signal propagation delay between the near end of the optical path and a respective reflective position. The present disclosure also relates to an optical time domain reflectometry system in which this method is implemented and a computer program having instructions to cause the optical time domain reflectometer and to execute the method herein.

Abstract: An optical endless phase shifting device includes a Mach-Zehnder structure operated in push-pull configuration and that creates a differential phase shift. The first stage outputs combined signals which are phase shifted by a phase shift of zero or ? in the second stage by phase shifters provided in both arms of the second stage or in a first arm only. These additionally phase-shifted signals are combined to at least one output signal. A control device controls the phase shifters such that endless shifting capability is provided by switching one of the phase shifters or the single phase shifter of the second stage to the respective other value when the differential phase shift reaches a given range of the differential phase shift of [0;?/2] in the configuration with two phase shifters in the second stage or [0;?/2] in the configuration with only one phase shifters in the second stage.

Abstract: The invention relates to a method for interrogating at least one optical sensor that is provided within or connected to an optical path at a sensor position, the optical path connecting the optical sensor to a near end of the optical path. The at least one optical sensor has a known frequency-dependent course of its reflectivity that is changed by a physical parameter to be sensed, especially the temperature or humidity of the environment surrounding the at least one optical sensor or the pressure being exerted onto the at least one optical sensor.

Abstract: The invention relates to a method for optically sensing a parameter of the group of temperature, humidity or mechanical stress using at least one optical sensor which includes a chirped Bragg grating and an optical reference reflector.

Abstract: The present disclosure relates to an optical time domain reflectometry method including the steps of feeding a plurality of unipolar optical probe signals to a near end of an optical path under test, receiving a corresponding plurality of reflected unipolar optical receive signals, creating a corresponding plurality of digital receive data signals, calculating at least one correlation signal by correlating the digital receive data signals with a bit sequence corresponding to a respective probe bit sequence, and determining the signal propagation delay between the near end of the optical path and a respective reflective position. The present disclosure also relates to an optical time domain reflectometry system in which this method is implemented and a computer program having instructions to cause the optical time domain reflectometer and to execute the method herein.

Abstract: Disclosed is a method for determining the link latency of an optical transmission link which includes an end node at each end and one or more pass-through nodes. Each pair of neighboring nodes is connected, at a connection port of each node, by an optical connecting path. Each pass-through node includes an optical pass-through path between its connection ports. The optical connecting paths and optical pass-through paths form an optical link path. A delimiter device includes a delimiter element provided at each connection port of each node. The delimiter element forms a demarcation within the optical link path.

Abstract: An optical endless phase shifting device includes a Mach-Zehnder structure operated in push-pull configuration and that creates a differential phase shift. The first stage outputs combined signals which are phase shifted by a phase shift of zero or ? in the second stage by phase shifters provided in both arms of the second stage or in a first arm only. These additionally phase-shifted signals are combined to at least one output signal. A control device controls the phase shifters such that endless shifting capability is provided by switching one of the phase shifters or the single phase shifter of the second stage to the respective other value when the differential phase shift reaches a given range of the differential phase shift of [0;?/2] in the configuration with two phase shifters in the second stage or [0;?/2] in the configuration with only one phase shifters in the second stage.

Abstract: The invention relates to a method for optically sensing a parameter of the group of temperature, humidity or mechanical stress using at least one optical sensor which includes a chirped Bragg grating and an optical reference reflector.

Abstract: The invention relates to a method of determining a time-of-flight of an optical signal between a starting point and a reflection point of an optical path, comprising: supplying to the path at least one optical probing signal; detecting an electrical return signal according to an optical return signal returning from the path in response to a corresponding one of the probing signals using direct detection; deriving at least one receive code sequence by sampling and slicing the return signal using a sampling rate corresponding to a bit rate of a sequence of pulses of the probing signal; determining a correlation function by correlating the transmit code sequence and the at least one receive code sequence; and identifying a main peak of the correlation function that corresponds to the reflection point and a time position of the peak, and determining the time-of-flight as the time position of the peak.

Abstract: A method and apparatus for performing event-driven diagnostics and/or prognostics of a network behaviour of a hierarchical optical network comprising the steps of recording at least one set of historical multi-level events representing different hierarchy levels of said optical network; mining of machine learned event patterns within the recorded multi-level events; mapping the determined mined event patterns to a multi-level network topology of said optical network and/or to a channel connectivity of channels through said optical network; and matching observed real-time multi-level target events of said optical network with at least one of the previously determined mined event patterns and performing a unified cause and effect analysis of network states and/or network components of said optical network for a recognized matching event pattern using the network topology and/or channel connectivity associated with the matching event pattern.

Abstract: Disclosed is a method for determining the link latency of an optical transmission link which includes an end node at each end and one or more pass-through nodes. Each pair of neighboring nodes is connected, at a connection port of each node, by an optical connecting path. Each pass-through node includes an optical pass-through path between its connection ports. The optical connecting paths and optical pass-through paths form an optical link path. A delimiter device includes a delimiter element provided at each connection port of each node. The delimiter element forms a demarcation within the optical link path.

Abstract: The invention relates to a method of determining a time-of-flight of an optical signal between a starting point and a reflection point of an optical path, comprising: supplying to the path at least one optical probing signal; detecting an electrical return signal according to an optical return signal returning from the path in response to a corresponding one of the probing signals using direct detection; deriving at least one receive code sequence by sampling and slicing the return signal using a sampling rate corresponding to a bit rate of a sequence of pulses of the probing signal; determining a correlation function by correlating the transmit code sequence and the at least one receive code sequence; and identifying a main peak of the correlation function that corresponds to the reflection point and a time position of the peak, and determining the time-of-flight as the time position of the peak.

Abstract: An optical time-domain reflectometer, OTDR, apparatus is configured to measure a backscattered trace of a fiber link under test (FLUT). The OTDR apparatus includes at least one photo diode adapted to detect an optical signal reflected from points along the fiber link under test in response to an optical test signal generated by a laser of the OTDR apparatus and supplied to the fiber link under test. The reflected optical test signal is attenuated or amplified automatically such that the power of the optical signal received by the photodiode is limited to a predetermined power range.

Abstract: A method and apparatus for performing event-driven diagnostics and/or prognostics of a network behaviour of a hierarchical optical network comprising the steps of recording at least one set of historical multi-level events representing different hierarchy levels of said optical network; mining of machine learned event patterns within the recorded multi-level events; mapping the determined mined event patterns to a multi-level network topology of said optical network and/or to a channel connectivity of channels through said optical network; and matching observed real-time multi-level target events of said optical network with at least one of the previously determined mined event patterns and performing a unified cause and effect analysis of network states and/or network components of said optical network for a recognized matching event pattern using the network topology and/or channel connectivity associated with the matching event pattern.