Exfo Inc.

Exfo Optics, Sas

Bernard Ruchet

Normand Cyr

Gang He

Daniel Gariepy

Mario L'Heureux

Etienne Morin-Drouin

Robert Baribault

Mathias Westlund

Stéphane Perron

Michel Leblanc

Mats Skold

Henrik Sunnerud

Peter Andrekson

Hongxin Chen

Denis Lafrance

Eric Girard

There is provided a method for measuring the PDL of a DUT as a function of the optical frequency &#x3bd; within a spectral range, which uses a single wavelength scan over which the input-SOP varies in a continuous manner. The power transmission through the DUT, curve T(&#x3bd;), is measured during the scan and the PDL is derived from the sideband components of the power transmission curve T(&#x3bd;) that results from the continuously varying input-SOP. More specifically, the Discrete Fourier Transform (DFT) of the power transmission curve T(&#x3bd;) is calculated, wherein the DFT shows at least two sidebands. At least two sidebands are extracted and their inverse DFT calculated individually to obtain complex transmissions(&#x3bd;),=&#x2212;J . . . J, where J is the number of sidebands on one side. The response vector |m(&#x3bd;)of the DUT is derived from the complex transmissions(&#x3bd;) and a matrixdetermined by the continuous trajectory of the SOP of the input test lightwave; and the PDL of the DUT as a function of &#x3bd; (PDL curve) is derived therefrom.

Polarization dependent loss measurement

Method and systems for characterizing an optical signal propagating along a communication link are disclosed. The signal includes a data-carrying signal contribution, modulated at a symbol frequency, and a noise contribution. The method includes measuring an optical power spectrum of the signal, which includes a data-carrying signal spectrum component and a noise spectrum component. The method also includes determining a measured spectral correlation function within pairs of spectral components of the signal as a function of center frequency of the pairs, the spectral components in each pair being spectrally separated from each other by the symbol frequency. The method further includes obtaining a solution for the data-carrying signal spectrum component based on the measured optical power spectrum, such that a calculated spectral correlation function based on the solution matches the measured spectral correlation function. In some embodiments, the spectral correlation function is measured as a low-frequency beatnote amplitude function.

Noise-free measurement of the spectral shape of a modulated signal using spectral correlation

A device and method for optical power measurement in an optical network supporting upstream and downstream signal propagation along an optical transmission path. An upstream wavelength analyzer receives upstream light extracted from the optical transmission path and is configured to determine an upstream spectral characteristic of the extracted upstream light. A downstream optical power meter assembly receives downstream light extracted from the optical transmission path and is configured to measure an optical power parameter of a downstream signal. A processing unit is configured to determine, based on the upstream spectral characteristic, at least one pass/fail threshold associated with the measured optical power parameter of the downstream signal.

Optical power measurement in a passive optical network

A device and method for optical power measurement in an optical network supporting upstream and downstream signal propagation along an optical transmission path. The device includes an upstream wavelength analyzer receiving upstream light extracted from the optical transmission path and configured to determine an upstream spectral characteristic of the extracted upstream light. The device also includes a downstream filter assembly receiving downstream light extracted from the optical transmission path and configured to spectrally split the extracted downstream light into a plurality of downstream signals, one of which corresponding to a downstream signal of interest. The device further includes a processing unit configured to identify, based on the upstream spectral characteristic, the downstream signal of interest among the downstream filtered signals, and a downstream optical power meter assembly coupled to the downstream filter assembly and configured to measure an optical power parameter of the downstream signal of interest.

A multimode launch system to be connected to an Optical Time-Domain Reflectometer (OTDR) for use in performing at least one OTDR measurement on a multi-fiber array Device Under Test (DUT), the multimode launch system comprising: an optical switch being connectable to the OTDR during use; a launch array device having an end being connectable to the optical switch and another end being connectable to the multi-fiber array DUT during use, the launch array device having a plurality of multimode launch optical fibers each having at least one first guidance parameter being smaller than a corresponding one of at least one second guidance parameter of at least one multimode optical fiber of the optical switch; and a multi-fiber mode conditioner along the launch array device for inducing a preferential attenuation of higher-order optical modes of test light propagated into the multi-fiber array DUT during use.

Multimode launch systems for use in performing an OTDR measurement on a multi-fiber array DUT and method of performing same

An inspection system for inspecting a multiple-fiber connector is provided. The inspection system includes a microscope probe and a probe tip configured to provide an optical path between the microscope probe and the multiple-fiber connector. The probe tip and microscope probe are configured so that the field of view of the microscope probe is sufficiently large to cover a portion of the connector surface encompassing a plurality of the optical fiber endfaces. The system further includes a shifting mechanism operable to shift the field of view of the microscope probe between at least two discrete positions over the connector surface. Each discrete position encompasses a different subset of the multiple optical fiber endfaces and optionally at least one positioning reference. A probe tip and a method of inspection are also provided.

Multiple-fiber connector inspection

A passive optical network (PON) device and method for optical power measurement along an optical transmission path supporting bidirectional propagation of downstream light and upstream light between two network elements of a PON is provided. The device includes an optical power splitter assembly extracting respective portions of the upstream and downstream light, and an upstream wavelength analyzer determining, from the extracted upstream light, an upstream spectral characteristic of the upstream light. The device also includes a processing unit determining, based on the upstream spectral characteristic, a downstream spectral characteristic of a downstream signal of interest among a plurality of downstream signals of the downstream light, and a downstream filter assembly filtering the extracted downstream light to select a portion of the downstream signal of interest. The device further includes a downstream optical power meter assembly measuring an optical power parameter of the selected portion of the downstream signal of interest.

There is provided a method for measuring an optical power attenuation value of a multimode DUT. The method generally has, using an optical source, propagating test light along a multimode device link having a first multimode device, the multimode DUT and a second multimode device serially connected to one another; said propagating including inducing a preferential attenuation of high-order optical fiber modes of the test light along the first multimode device and along the second multimode device; using an optical power detector, detecting an optical signal resulting from the propagation of the test light along the multimode device link and transmitting an output signal based on the detected optical signal; and using a processor, determining the optical power attenuation value of the multimode DUT based on the output signal.

Method and system for measuring an optical power attenuation value of a multimode device under test, receive device and computer-readable memory

A portable inspection probe for the inspection of a recessed mating surface of an optical fiber connector is provided. In one variant, the portable inspection probe includes a digital holographic detection module operable to digitally record a hologram of the recessed mating surface, and a rigid probe tip configured to be optically coupled to the digital holographic detection module and shaped to provide optical access to the recessed mating surface. In another variant, the portable inspection probe is to be used with a rigid probe tip connectable thereto, and the digital holographic detection module includes a probing optical assembly not traversed by a reference beam and configured to direct an object beam onto the recessed mating surface and to collect the object beam upon reflection thereof by the recessed mating surface. An inspection system and an inspection method are also provided.

Portable digital holographic probe for the inspection of optical fiber connectors, and inspection system and method for the same

A portable apparatus for measuring optical powers of optical signals propagating concurrently in opposite directions in an optical transmission path between two elements, at least one of the elements being operative to transmit a first optical signal (S) only if it continues to receive a second optical signal (S) from the other of said elements, comprises first and second connector means for connecting the apparatus into the optical transmission path in series therewith, and propagating and measuring means connected between the first and second connector means for propagating at least the second optical signal (S) towards the one of the elements, and measuring the optical powers of the concurrently propagating optical signals (S, S). The measurement results may be displayed by a suitable display unit. Where one element transmits signals at two different wavelengths, the apparatus may separate parts of the corresponding optical signal portion according to wavelength and process them separately.

Method and apparatus for testing transmission lines normally propagating optical signals

There is provided a method for determining a noise parameter characterizing an optical Signal-Under-Test (SUT) having a signal contribution, an Amplified Spontaneous Emission (ASE) noise contribution and a non-ASE optical noise contribution, such as a carrier-leakage contribution or a depolarized-signal contribution, within an optical-signal bandwidth. The method comprises acquiring optical spectrum trace(s) of the SUT, discriminating at least the non-ASE optical noise contribution from the ASE-noise contribution using the optical spectrum trace(s) and/or a trace obtained from the optical spectrum trace(s); and determining the noise parameter using discriminated non-ASE optical noise contribution and/or the discriminated ASE-noise contribution.

Characterization of non-ASE noise on optical signals

A portable apparatus for measuring parameters of optical signals propagating concurrently in opposite directions in an optical transmission path between two elements, at least one of the elements being operative to transmit a first optical signal (S) only if it continues to receive a second optical signal (S) from the other of said elements, comprises first and second connector means for connecting the apparatus into the optical transmission path in series therewith, and propagating and measuring means connected between the first and second connector means for propagating at least the second optical signal (S) towards the one of the elements, and measuring the parameters of the concurrently propagating optical signals (S, S). The measurement results may be displayed by a suitable display unit. Where one element transmits signals at two different wavelengths, the apparatus may separate parts of the corresponding optical signal portion according to wavelength and process them separately.

Portable apparatus for measuring parameters of optical signals propagating concurrently in opposite directions in an optical transmission path between two elements, at least one of the elements being operative to transmit a first optical signal (S) only if it continues to receive a second optical signal (S) from the other () of said elements, comprises first and second connectors for connecting the apparatus into the optical transmission path in series therewith, and a device connected between the first and second connectors for propagating at least the second optical signal (S) towards the one of the elements, and measuring the parameters of the concurrently propagating optical signals (S, S). The measurement results may be displayed by a suitable display unit. Where one element transmits signals at two different wavelengths, the apparatus may separate parts of the corresponding optical signal portion according to wavelength and process them separately.

An optical sampling arrangement for high-speed measurement of the time-varying electric field of an optical input signal utilizes coherent mixing of the optical input signal with a reference laser source in a phase-diverse optical hybrid solution, followed by optical sampling of the coherently-mixed fields at the output of the optical hybrid. The generated streams of optical samples are then detected and signal processed in order to reconstruct a sampled version of the electric field of the original optical input signal.

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Bernard Ruchet