According to a laser beam output apparatus, a pulsed laser output section outputs a laser beam having a predetermined wavelength as first pulses. An optical path determining section receives the first pulses and determines one among a plurality of optical paths for each of the first pulses for output. A parallelizing section parallelizes the traveling direction of light beams traveling, respectively, through the plurality of optical paths. A wavelength changing section receives outputs from the parallelizing section and changes the outputs to have their respective different wavelengths for output. A focusing section receives and focuses outputs from the wavelength changing section. An optical fiber receives an output from the focusing section at a core end face. The focusing section is arranged to focus the outputs from the wavelength changing section on the core end face.

A transmitter generates a first electrical signal comprising a first low-frequency signal, an empty period, and a pump pulse having a first frequency; and a second electrical signal comprising a second low-frequency signal and at least two probe pulses, each probe pulse having a second frequency that differs from the first frequency. The transmitter modulates first and second optical subcarriers having different polarizations using the first and second electrical signals, respectively. The transmitter generates an optical signal from the first and second optical subcarriers, wherein the first and second low-frequency signals overlap in time, wherein the empty period overlaps in time with one of the probe pulses, and wherein the pump pulse overlaps in time with another one of the probe pulses. The optical signal is detected at a receiver over an optical link, and the receiver uses the optical signal to estimate nonlinear phase shift in the optical link.

A method of identifying and testing an optical fiber includes emitting light into the optical fiber. The light includes an identification signal and a testing signal. The method also includes reading the identification signal and the testing signal with a single device. The method further includes determining an identity of the optical fiber based on the identification signal with the single device and determining a status of the optical fiber based on the testing signal with the single device.

Aspects of the present disclosure describe systems, methods and structures providing bipolar cyclic coding for Brillouin optical time domain analysis that may be employed—for example—to determine high accuracy temperature and/or strain measurements along an optical fiber. Systems, methods, and structures according to the present disclosure employ the bipolar cyclic coding technique that advantageously overcomes the problems that plague the prior art and provides extended sensing range resulting from superior signal-to-noise characteristics.

A system includes at least one waveguide with optical interaction portions that represent a sequence of reference symbols based on the order of the optical interaction portions in the at least one waveguide. At least one light source sends photons of one or more predetermined wavelengths into the at least one waveguide representing a string of query symbols. A detector detects photons received from the at least one waveguide that result from optical interactions between photons sent into the at least one waveguide and one or more corresponding optical interaction portions with an interaction between photons and an optical interaction portion indicating a match between a query symbol and a reference symbol. An analyzer determines one or more respective relative locations of the one or more corresponding optical interaction portions indicating one or more relative locations of the string of query symbols in the reference sequence.

There is provided an OTDR receive device and an OTDR system comprising an OTDR receive device wherein the OTDR unit and the OTDR receive device are to be connected at opposite ends of an optical fiber link under test. The OTDR receive device comprises means for the OTDR system to detect an established connectivity between the OTDR unit and the OTDR receive device via the optical fiber link under test and a status indicator to notify a user of the receive device of the connectivity status and optionally an OTDR measurement status. Connectivity detection allows to check for continuity between the OTDR unit and the OTDR receive device before launching an OTDR measurement. A user of the OTDR unit does not need to communicate with the user of the OTDR receive device to know when to start the acquisition.

There is provided an OTDR receive device, an OTDR system comprising an OTDR receive device and an OTDR method wherein the OTDR unit and the OTDR receive device are to be connected at opposite ends of an optical fiber link under test. The OTDR receive device comprises means for the OTDR system to detect an established connectivity between the OTDR unit and the OTDR receive device via the optical fiber link under test and a status indicator to notify a user of the receive device of the connectivity status and optionally an OTDR measurement status. Connectivity detection allows to check for continuity between the OTDR unit and the OTDR receive device before launching an OTDR measurement. A user of the OTDR unit does not need to communicate with the user of the OTDR receive device to know when to start the acquisition.

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.

A system and method for distributed dynamic strain measurement using optical fiber that is based on Brillouin optical time-domain reflectometry (BOTDR) with stimulated Brillouin scattering (SBS). A short-time Fourier transform (STFT) is used to rebuild the Brillouin frequency shift (BFS) of the SBS scattered signal to perform the dynamic strain measurement.

In some examples, automatic OTDR-based testing may include determining, based on analysis of a signal that is received from a DUT that is to be monitored, whether the DUT is optically connected. Based on a determination that the DUT is optically connected, a measurement associated with the DUT may be performed.