Abstract: A cable assembly may include an outer jacket, a printer circuit board including light emitting diodes, and a cable configured to transmit information. The outer jacket may include a channel opening and the printed circuit board may be configured to be positioned within the channel opening and between the cable and the outer jacket. Another cable assembly may include an inner jacket, an outer jacket, a printed circuit board including light emitting diodes, and a cable configured to transmit information. The inner jacket may include a channel opening, and the printer circuit board may be configured to be positioned within the channel opening and between the inner jacket and the outer jacket.

Abstract: Detecting the source of a defect in a cable may be difficult, in part because present systems may be configured to wind and unwind the cable on many different spools, capstans or other transport equipment. Provided are systems and methods in which a laser speed gauge is used to measure the rotation of a cable assembly component and determine any abnormalities in the rotation (e.g., vibrations, periodic increases/decreases in speed). An example method includes receiving, by a computing device and from a laser speed gauge, a first reading of a rotating cable assembly component. The computing device may covert the first reading of the rotating cable assembly component to a frequency analysis of the rotating cable assembly component and determine based on the frequency analysis of the rotating cable assembly component, a structural defect in a cable caused by the rotating cable assembly component.

Abstract: A laser tuning system includes an optical transmitter having a tunable laser that transmits optical signals at various wavelengths to an optical fiber through an optical component, which attenuates a range of wavelengths of the optical signal. An optical detector detects optical returns that have been reflected from the fiber at points beyond the optical component. A tuning control module analyzes the optical returns in order to provide a tuning value for tuning the laser to a desired wavelength. As an example, the laser may be tuned in order to maximize or otherwise increase the amount of optical power passing through the optical component.

Abstract: A device for calibrating distributing sensing technologies is presented. The device includes an optical fiber, a first input arranged for receiving at least one optical pulse and injecting this at least one optical pulse towards the optical fiber, an output arranged for receiving a backscattered signal generated in the optical fiber. The optical fiber includes at least one event, each event being a part of the optical fiber and having at least one modified physical state or property that is different from the physical state or property of the rest of the optical fiber. The device includes structure creating different optical paths for the at least one optical pulse, the different optical paths having different lengths, each optical path passing through the at least one event. The invention also relates to a process implemented in the device.

Abstract: A system for testing continuity of a cable assembly includes an optical time domain reflectometry (OTDR) device selectively coupled to an input connector of a cable and a design database storing cable data. The cable data indicates at least a length of the cable. The system includes a processor and memory in communication with the processor. The processor is configured to execute instructions stored on the memory which cause the processor to receive the cable data from the design database, receive OTDR data associated with the cable from the OTDR device, and calculate a distance-to-fault based on the OTDR data. In response to the distance-to-fault being less than the length of the cable, the processor determines that a connectivity failure has occurred with the cable and generates fault data indicating the connectivity failure.

Abstract: A method in a transceiver apparatus for monitoring an optical link over which one or more data signals are to be transmitted comprises time interleaving a test signal with an auxiliary management and control channel, AMCC, signal to form a time-interleaved signal. The time-interleaved signal is transmitted with one or more downstream data signals over the optical link. A backscattered test signal is received to monitor the optical link.

Abstract: Systems and method include a detector communicatively coupled to a fiber span; and processing circuitry connected to the detector and configured to digitally sample and process an output of the detector, detect phase changes in the output, and identify an electrostrictive response of the fiber span based on the detected phase changes and based on a dependence of the detected phase changes with frequency. A property of the fiber span can be determined on the electrostrictive response. The property of the optical fiber can include one or more of optical fiber material type, optical fiber material property, optical fiber area, optical fiber geometry, optical fiber condition, optical fiber stress and strain, optical fiber temperature. and optical fiber radiation exposure.

Abstract: An inspection device for an optical ferrule includes one or more reflectors. Each reflector has a mating surface and a mirror disposed at an oblique angle with respect to the mating surface. Each reflector is configured to mate with the optical ferrule when the optical ferrule is disposed within a housing of an optical connector. When the mating surface of the reflector is in mated contact with the mating surface of the optical ferrule, the mirror is positioned to provide a reflected view of at least a portion of a mating surface of the optical ferrule.

Abstract: The invention relates to an optoelectronic distributed measuring device based on optical fiber, said device comprising a continuous light source (1) emitting a continuous light signal at a first frequency ?0, an acousto-optical modulator (6) capable of transforming said continuous signal into a pulse signal to be injected into an optical fiber (15) to be tested, and a photodetection module (10) capable of detecting a backscattering signal from a Rayleigh backscattering and a spontaneous Brillouin backscattering from said optical fiber (15) to be tested, said device being characterized in that it further comprises a first coupler (3) and a second coupler (9), said second coupler (9) being capable of mixing the signal of the local oscillator with the backscattering signal from said optical fiber (15) to be tested before transmitting it to the photodetection module (10), the backscattering signal being modulated at least at a frequency ?rB equal to ?0??bref+?A+?bAS, where ?bAS is the anti-Stokes Brillouin (backs

Abstract: Aspects of the present disclosure describe systems, methods and structures for distributed fiber sensing systems including interrogator and attached fiber in which the interrogator includes a common line card and function-specific, pluggable front end in which the line card is configurable and supports different signal processing paths and automatically senses the front-end type and uses corresponding firmware/software or signal processing path(s) to process sensed data.

Abstract: An optical power monitor device includes a first optical fiber, including a core and a cladding surrounding the core and being at least one of an incidence-side optical fiber and a launch-side optical fiber connected to each other at a connection point, which is constituted by a curve portion and a linear portion between the curve portion and the connection point, a low refractive index layer that is provided in at least a portion of the linear portion on an outer side of the cladding and has a refractive index lower than a refractive index of the cladding, and a first optical detector that is provided at a position close to at least the curve portion.

Abstract: Aspects of the present disclosure describe systems, methods and structures for classification of higher-order spatial modes using machine learning systems and methods in which the classification of high-order spatial modes emitted from a multimode optical fiber does not require indirect measurement of the complex amplitude of a light beam's electric field using interferometry or, holographic techniques via unconventional optical devices/elements, which have prohibitive cost and efficacy; classification of high-order spatial modes emitted from a multimode optical fiber is not dependent on a light beam's alignment, size, wave front (e.g. curvature, etc.

Abstract: A method of distinguishing whether a detected change in reflected power in an optical time domain reflectometer (OTDR) measurement carried out in a fiber optic transmission system (16) using an OTDR is caused by a an event causing actual attenuation or a change in a mode field diameter, comprising the steps of emitting a succession of first sampling light pulses of a first wavelength into the fiber optic transmission system (16) while a pumping signal with a second wavelength is emitted into the fiber optic transmission system (16), and measuring a first OTDR trace (34?) resulting from the reflection of the first sampling light pulses in the fiber optic transmission system (16), such that the first sampling light pulses and their reflections interact with the pumping signal via stimulated Raman scattering.

Abstract: An inspection device of an optical fiber unit, including a plurality of binding materials wound in an SZ shape on a plurality of optical fibers, includes: a measurement sensor that measures a width of the optical fiber units in a first direction orthogonal to a longitudinal direction in which the optical fiber unit extends; and a determination circuit that determines a presence or an absence of an abnormality in a binding state, based on a measurement result of the measurement sensor.

Abstract: A multi-core fiber includes multiple optical cores, and for each different core of a set of different cores of the multiple optical cores, a total change in optical length is detected. The total change in optical length represents an accumulation of all changes in optical length for multiple segments of that different core up to a point on the multi-core fiber. A difference is determined between the total changes in optical length for cores of the set of different cores. A twist parameter and/or a bend angle associated with the multi-core fiber at the point on the multi-core fiber is/are determined based on the difference.

Abstract: The present invention relates to a precision measurement system using an interferometer and an image, comprising: an interferometer for measuring a distance to a movable object by a transfer device; an imaging device which is fixed at a specific position and captures an image of an object located within a specific range; and a control device which calculates absolute coordinates indicating a distance from a reference point to each pixel of the image on the basis of the distance measured by the interferometer and the image obtained by the imaging device, calculates an absolute distance between the pixels of the image on the basis of the absolute coordinates, and measures a length of the object captured by the imaging device using the absolute coordinates or the absolute distance.

Abstract: Aspects of the present disclosure describe a multilayer coding method for physical value measurements in which a multi-pulse pattern is generated through several layers, each of which is encoded with a different cyclic codeword. The total coding gain is the product of the gains of each layer advantageously allowing a long cyclic codeword to be replaced by combining several short cyclic codewords. Of particular advantage, methods according to the present disclosure provide better signal-to-noise characteristics, longer sensing distances and lower computational complexity particularly suitable for high-performance and cost-effective distributed optical fiber sensing (DOFS).

Abstract: In one embodiment, a transmission system includes a transmitter, a receiver, and a filter operable at one of the transmitter and the receiver to remove channel impairments. The filter is operable according to a sum of a Gaussian function and a reciprocal of cosine function, wherein the Gaussian and reciprocal of cosine functions comprise tunable parameters to account for skew and channel asymmetry.

Abstract: Describe are an OPGW single wire torsional fatigue test method, apparatus and storage medium. The method includes: a preset torsional angle and preset cycle number of torsions of an OPGW single wire are acquired (S1); forward and backward torsional forces are sequentially and alternately applied to the OPGW single wire according to the preset torsional angle (S2); when a number of application times of the applied torsional forces reaches a preset cycle number of torsions, torsional force application to the OPGW single wire is stopped (S3). According to the test method, a bidirectional torsional fatigue test on the OPGW single wire may be made by sequentially and alternately applying the forward and backward torsional forces to the OPGW single wire, so that reliability of a test result and test efficiency are improved.

Abstract: An optical fiber sensing system includes a sensing optical fiber and one or more optical amplifiers in series with the sensing fiber and arranged to increase the power of sensing pulses travelling along the fiber to thereby increase the range of the sensing system. The optical fiber sensing system is one selected from the group including an optical fiber distributed acoustic sensor (DAS), an optical fiber distributed temperature sensor (DTS), or an optical time domain reflectometry (OTDR) system.

Abstract: The nondestructive determination of core size of a hollow-core photonic bandgap fiber (HC-PBF) using Fabry-Perot (FP) interference is performed with an apparatus including a tunable laser source (TLS), a 1×2 single-mode (SM) coupler, an SM collimator, a six-axis translation stage, an optical detector, and an oscilloscope. The light from the TLS passes through the 1×2 SM coupler and the SM collimator to perpendicularly enter two parallel air-SiO2 interfaces of the core of the fiber and is reflected, while the TLS is tuned from one wavelength to another. Then the reflected spectrum is guided to the optical detector, where its interference intensity is converted into voltage intensity to be displayed at the oscillator and fitted with a least-squares method to obtain the distance between the two air-SiO2 interfaces. The core size of the fiber can be obtained by rotating the fiber and repeating the procedure at multiple angular positions.

Abstract: A measurement system for performing measurement by Brillouin scattering analysis, the system comprising a laser emitter device (10) configured to emit an incident wave (?0) and a reference wave (?0??B), the incident wave presenting an incident frequency (?0) and the reference wave presenting a reference frequency (?0??B), the reference frequency (?0??B) being shifted from the incident frequency (?0) by a predetermined value (?B). The system is configured to: project the incident wave (?0) into the optical fiber (25); receive in return a backscattered wave (?0??S); generate a composite wave (?0-S, 0-B) combining the backscattered wave (?0??S) and the reference wave (S0??B); and determine at least one property relating to the fiber by analyzing a Brillouin spectrum of the composite wave (?0-S, 0-B). Advantageously, the incident wave and the reference wave come from a dual-frequency vertical-cavity surface-emitting laser source (12) forming part of the laser emitter device.

Abstract: The present invention relates to a method and system of obtaining a twist rate of a twist applied to an optical fiber (12) about a longitudinal axis of the optical fiber (12) at least in a part along a length of the optical fiber, the optical fiber (12) having a center core (16) extending along the length of the optical fiber (12) and at least one outer core (14, 18, 20) helically wound around the center core (16) with a spin rate.

Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.

Abstract: 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.

Abstract: A Raman probe includes: a first illuminating fiber and a second illuminating fiber that are arranged in series and that are formed of different materials from each other; a coupling optical system for optically coupling the first and second illuminating fibers; a light-collecting fiber that is formed of the same material as the second illuminating fiber and that collects Raman scattered light from an examination subject; and an optical filter that is disposed between the first and second illuminating fibers and that selectively transmits a laser beam being guided by the first illuminating fiber and, of Raman scattered light of the first illuminating fiber excited by the laser beam, Raman scattered light the amount of Raman shift of which is smaller than a predetermined amount of Raman shift in a Raman spectrum of the examination subject.

Abstract: In order to provide an inspection device capable of quantitatively evaluating a pattern related to a state of a manufacturing process or performance of an element, it is assumed that an inspection device includes an image analyzing unit that analyzes a top-down image of a sample in which columnar patterns are formed at a regular interval, in which an image analyzing unit 240 includes a calculation unit 243 that obtains a major axis, a minor axis, an eccentricity, and an angle formed by a major axis direction with an image horizontal axis direction of the approximated ellipse as a first index and a Cr calculation unit 248 that obtains a circumferential length of an outline of a columnar pattern on the sample and a value obtained by dividing a square of the circumferential length by a value obtained by multiplying an area surrounded by the outline and 4? as a second index.

Abstract: A visual fault locator includes a housing; a receptacle retained by the housing and configured to receive a connector of a fiber optic cable under test; a light source retained by the housing and positioned relative to the receptacle to emit light into a filament of the fiber optic cable under test; and an interface in the form of an electrical connector retained by the housing. The housing is physically configured so as to be installed in and removed from a port of a host device, such as a network communications. The visual fault locator receives operational power for the light source from the host device via the interface. Optionally, operational commands for controlling a state of the light source are received from the host device over the interface.

Abstract: The application provides a method for measuring a dispersion coefficient of an optical fiber. A network device sends a first optical supervisory channel (OSC) measurement signal and a second OSC measurement signal, where wavelengths of the first OSC measurement signal and the second OSC measurement signal are different. The network device receives the returned first OSC measurement signal and second OSC measurement signal, where the first OSC measurement signal and the second OSC measurement signal are transmitted through a first optical fiber and a second optical fiber to return to the network device, and the first optical fiber and the second optical fiber are a to-be-tested optical fiber. The network device determines a delay difference between the received first OSC measurement signal and second OSC measurement signal. The network device determines a dispersion coefficient of the to-be-tested optical fiber based on the delay difference.

Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.

Abstract: An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.

Abstract: An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, the beat signal may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.

Abstract: A variable-frequency light source is configured to emit a light beam and modulate a frequency of the light beam. A fiber optic cable is attached to the variable frequency light source. The fiber optic cable is configured to receive the light beam at an inlet and pass the light beam to an exit. Multiple optical detectors are attached to the fiber optic cable. Each of the optical detectors is configured to detect a specified frequency of light that is backscattered through the fiber optic cable. An actuation mechanism is attached to the fiber optic cable. The actuation mechanism is configured to deform the fiber optic cable in response to a stimulus.

Abstract: A variable-frequency light source is configured to emit a light beam and modulate a frequency of the light beam. A fiber optic cable is attached to the variable frequency light source. The fiber optic cable is configured to receive the light beam at an inlet and pass the light beam to an exit. Multiple optical detectors are attached to the fiber optic cable. Each of the optical detectors is configured to detect a specified frequency of light that is backscattered through the fiber optic cable. An actuation mechanism is attached to the fiber optic cable. The actuation mechanism is configured to deform the fiber optic cable in response to a stimulus.

Abstract: The present invention is an Optical Time-Domain Reflectometer (OTDR) with an integrated Launch Cable that has a retractable lead, designed to work as a standalone instrument, or under the control of an external device such as a smartphone, tablet, PC, or server.

Abstract: A method of manufacturing a side-coupling structure, associated with coupling an aiming beam from an aiming beam fiber into a laser beam fiber, may include removing a coating from a section of the laser beam fiber and removing a coating from a section of the aiming beam fiber. The method may further include bringing the section of the aiming beam fiber in physical contact with the section of the laser beam fiber in order to create the side-coupling structure. The method may further include recoating the section of the laser beam fiber and the section of the aiming beam fiber in order to coat the side-coupling structure.

Abstract: In some examples, an optical time-domain reflectometer (OTDR) device may include a laser source to emit a plurality of laser beams. Each laser beam may include a different pulse width. A control unit may analyze, for each laser beam, a backscattered signal from a device under test (DUT). The control unit may generate, for each backscattered signal, a trace along the DUT. Further, the control unit may generate, based on an analysis of each trace along the DUT, a combined trace that identifies optical events detected along the DUT.

Abstract: The disclosure relates to a distributed optical fibre sensor having an optical switch arranged to selectively and simultaneously couple each of a plurality of interrogators to each of a plurality of sensing optical fibres.

Abstract: One or more embodiments are directed to optical test instruments, such as fiber optic inspection scopes and optical power meters, for testing optical communication links, such as fiber optic connectors. The optical test instruments include a single test port that is able to operate in two modes of operation. In a first mode of operation, the optical test instrument is configured to provide an image of the endface of a fiber optic connector under test. In a second mode of operation, the optical test instrument is configured to measure power or power loss in an optical fiber under test. In that regard, the fiber optic connector only has to be coupled to a single port of an optical test instrument for a visual inspection of an endface of a fiber optic connector and a power test of the optical fiber under test.

Abstract: A method of detecting tampering with a conveyance medium may include determining a baseline brightness level detected at opposing ends of an optical fiber segment disposed proximate to the conveyance medium, determining whether a change in brightness above a threshold level occurs, and providing an output indicating that a breach in continuity of a shielding material that shields both the conveyance medium and the optical fiber segment from exposure to ambient light has occurred in response to the change in brightness being above the threshold level.

Abstract: An optical transmitter using multiplexed optical signals increases in cost and in size in order to control an optical carrier frequency with high precision, therefore, an optical transmitter according to an exemplary aspect of the invention includes optical signal generating means for adding a first optical component to a first optical carrier and adding a second optical component to a second optical carrier; multiplexing means for multiplexing the first optical carrier and the second optical carrier to generate a multiplexed optical signal; monitoring means for monitoring the multiplexed optical signal to detect a monitor signal having a difference frequency between the first optical component and the second optical component; and controlling means for controlling a carrier frequency of at least one of the first optical carrier and the second optical carrier according to the monitor signal.

Abstract: A method for calibrating an OLTS includes calibrating a first optical power meter of the OLTS using a stabilized light source. The method further includes calibrating a second optical power meter of the OLTS using the stabilized light source. The method further includes setting a power of an internal light source using the calibrated first optical power meter. A calibration cable is connected to a first test port and a second test port during setting of the power level, and a connection of the calibration cord to the second test port is maintained between calibrating of the second optical power meter and setting of the power level.

Abstract: An optical fiber inspecting device is disclosed. The optical fiber inspecting device includes a first light-emitting unit that irradiates an optical fiber with a first light beam, the optical fiber including a glass fiber and a coating resin and moving in an axial direction, and a first light-receiving unit that receives scattered light resulting from the first light beam scattered in the optical fiber, and converts the scattered light to an electrical signal. An optical axis of the first light-receiving unit passes through an irradiation position where the first light beam strikes the optical fiber, and the first light beam and the optical axis of the first light-receiving unit diagonally intersect each other, thereby preventing the first light beam from directly entering the first light-receiving unit.

Abstract: An optical fiber status detection method includes: alternately sending, by a first station, an optical time domain reflectometer (OTDR) pulse and optical supervisory channel (OSC) data to a second station on a same channel, where the second station is a neighboring station of the first station; and receiving, by the first station, reflection light returned by the OTDR pulse by using an optical fiber between the first station and the second station, and obtaining an OTDR probe value according to the reflection light.

Abstract: The invention relates to a method for qualifying the actual effective modal bandwidth of a multimode optical fiber over a predetermined wavelength range, comprising the steps of: carrying out (30) a Dispersion Modal Delay (DMD) measurement of the multimode optical fiber at a single wavelength to obtain an actual DMD plot; generating (32) at least two distinct modified DMD plots from the actual DMD plot, each modified DMD plot being generated by applying to the recorded traces a temporal delay ?t that increases in absolute values with the radial offset value roffset, each modified DMD plot being associated with a predetermined bandwidth threshold (S1; S2); for each modified DMD plot, computing (33) an effective modal bandwidth as a function of said modified DMD plot and comparing (34) the computed effective modal bandwidth (EMBc1; EMBc2) with the bandwidth threshold value to which the modified DMD plot is associated; (35) qualifying the actual effective modal bandwidth as a function of results from the compari

Abstract: A distributed sensing fiber acoustic emission fusion sensing system includes a sensing fiber temperature-sensitive compensation device and a sensing fiber acoustic emission demodulation device. A sensing fiber in the sensing fiber temperature-sensitive compensation device after being compensated enters the sensing fiber acoustic emission demodulation device.

Abstract: A submarine optical repeater includes a submarine amplifier module, which further includes a pumping laser module and an optical detector module. The pumping laser module generates optical amplifications within an optical cable, and, in the case of a fault in the optical cable, the optical detector module detects at least one characteristic of an optical signal caused by the fault in the optical cable. This configuration then identifies a particular signal characteristic that indicates a fault within the optical cable.

Abstract: The invention provides an improved method and apparatus, in general, for a use of a sheaf of unclad waveguide beam-makers to provide for a multi-stage forcedly-conveying waveguide effect of waveguide fibers in combination with the self-focusing waveguide effect of parabolic antennas, on the one hand, to absorb the ambient radiation, and in particular, for sunlight rays energy absorption to detect and transform the energy into either warmth, or electrical power, or mechanical thrust, and, on the other hand, to transmit the wave-energy through a homogeneous poorly-permeable medium.

Abstract: According to examples, a fiber-optic testing source for testing a multi-fiber cable may include a laser source communicatively coupled to a plurality of optical fibers connected to a connector. The fiber-optic testing source may include at least one photodiode communicatively coupled to at least one of the plurality of optical fibers by at least one corresponding splitter to implement a communication channel between the fiber-optic testing source and a fiber-optic testing receiver. The communication channel may be operable independently from a polarity associated with the multi-fiber cable. The fiber-optic testing receiver may include a plurality of photodiodes communicatively coupled to a plurality of optical fibers.

Abstract: A monitoring and calibration apparatus for an optical networking device such as ROADM is provided. Reflectors are integrated into the device, for example at the ends of optical interconnect cables. The reflectors reflect light in specific monitoring wavelengths and pass other wavelengths such as those used for communication. A light source emits monitoring light which is reflected by the reflector and measured by a detector to measure the integrity of optical paths. The optical paths can include optical cables and cable connectors. Path integrity between different modules of the device can therefore be monitored. Multiple reflectors, reflecting light in different wavelengths, can be placed in series along the same optical path and used to monitor multiple segments of the path. A wavelength selective switch (WSS) of the device can be used to route monitoring light to different optical paths. The WSS also operates to route communication signals in the device.