Viavi Solutions Inc.

Jds Uniphase Corporation

Chris Wagner

Grant Tessaro

Joshua Philipson

Robert Matthew Adams

Josh Philipson

James Kirby Goulet

Eugene Chan

A test instrument tests an optical component of a fiber optic network. The test instrument determines signal parameters describing pulses to be emitted by lasers of the test instrument to test the optical component, and directly modulates the lasers to repeatedly emit the pulses at different wavelengths on a single fiber optic cable in a time division multiplexing manner. The test instrument triggers powering measurements to coincide with the emitted pulses, and determines performance parameters of the optical component based on the triggered power measurements.

Multi-wavelength pulsed optical test instrument

Mult-wavelength pulsed optical test instrument

According to an example, a polarization control system is to manipulate polarization manipulators to output light that achieves a trajectory on a Poincar&#xe9; sphere that tracks a known trajectory of a polarizer on the Poincar&#xe9; sphere, in which the trajectory of the output light enables definition of a reference polarization state of the output light. The polarization control system may also manipulate an output polarization manipulator to set the output light to a predefined polarization state based upon the reference polarization state.

Polarization control based upon a polarization reference state

According to an example, a plurality of pixels of a modulator upon which an input light beam impinges may be modulated to apply a first asymmetrical attenuation pattern on the input light beam and to direct a first attenuated light beam from the modulator and a first power level of the first attenuated light beam may be measured. The plurality of pixels may be modulated to apply a second asymmetrical attenuation pattern on the input light beam and to direct a second attenuated light beam from the modulator, and a second power level of the second attenuated light beam may be measured. A difference between the first power level and the second power level may be calculated and a modified peak frequency for an attenuated light beam from the calculated difference may be calculated.

Attenuated light beam peak frequency modification

According to an example, an optical transmission device may include a spatial light modulator having a plurality of cells, in which different wavelengths of a light beam are to impinge upon different groups of pixels along a dispersion direction. The device may also include a driver mechanism to modulate, at a first frequency, a first group of the plurality of cells upon which light having a first wavelength impinges to impress a first frequency fluctuation onto a property of an output light including the first wavelength and to modulate, at a second frequency, a second group of the plurality of cells upon which light having a second wavelength impinges to impress a second frequency fluctuation onto a property of an output light including the second wavelength, in which the second frequency modulation differs from the first frequency modulation.

Spectral analysis using a spatial light modulator

An optical power meter including a photodiode having a surface for receiving a beam of light, a thermo-electric cooler for maintaining the photodiode at a predetermined temperature, and a current monitor for measuring a drive current passing through the thermo-electric cooler allows dark current drift arising from a varying thermal gradient across the active region of the photodiode to be corrected, thus improving stability of the optical power meter. More specifically, by monitoring the TEC drive current, and applying a correction factor to the optical power readings, the stability of optical power readings is improved by an order of magnitude.

Method for correcting for dark current variation in TEC cooled photodiodes

A source generates an optical test signal sweeping a bandwidth of wavelengths over time. The test signal is applied to a device under test (DUT) to generate a response signal. A timing signal generator connected to the source generates a timing signal having triggers at time instances corresponding to known wavelengths of the test signal. A DUT detector samples the DUT response signal generating sampled DUT data using a sampling period that is shorter than a shortest time between timing signal triggers. A correlator receives the timing signal, the known wavelengths associated with the timing signal triggers, the sampled DUT data and the DUT detector sampling period then correlates each sampled DUT datum to a wavelength of the test signal that was applied to the DUT when the DUT datum was sampled by interpolating the known wavelengths using the trigger time instances and the DUT detector sampling period.

High resolution wavelength measurement system using a coarse, stable timing signal

A tunable laser system having fine and coarse wavelength discrimination is provided. The tunable laser system includes a first filter having a first free spectral range (FSR) and a second filter having a second FSR different from the first FSR. The first filter provides a first series of pulses from a first portion of a laser output, and a second filter provides a second series of pulses from a second portion of the laser output. A processing system compares the first series of pulses and the second series of pulses to identify a series of markers, in which the markers are separated by a beat period of the first series of pulses and the second series of pulses. Advantageously, the series of markers may be used for mode-hop detection and/or for wavelength referencing.

Growing community of inventors

Kanata, Canada

Chris Wagner