# US 2019/0170608 A1 · Methods and assemblies for using electrostriction to characterize properties of optical fiber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170608 A1 - Document ID: US20190170608A1 - Status: Published application - Kind: A1 - Application number: 15/828,497 - Filed: 2017-12-01 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Ciena Corporation - Applicants: Ciena Corporation - Inventors: Andrew D. SHINER; Michael Andrew REIMER; Maurice O'SULLIVAN - Web page: https://patentgrep.com/patent/US20190170608A1 ## CPC - G01M 11/33: {with a light emitter being disposed at one fibre or waveguide end-face, and a light receiver at the other end-face} - H04B 10/0731: {Testing or characterisation of optical devices, e.g. amplifiers} - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - H04B: TRANSMISSION ## Abstract Methods and assemblies for determining a property or environment of an optical fiber, including: measuring a frequency dependent electrostrictive response of an optical fiber; and based on the measured frequency dependent electrostrictive response, determining a property of the optical fiber. The property or environment of the optical fiber includes one or more of optical fiber type, optical fiber material type, optical fiber material property, optical fiber area, optical fiber geometry, optical fiber condition, optical fiber stress and strain, optical fiber environment, optical fiber temperature, optical fiber routing, optical fiber spooling, and optical fiber radiation exposure. ## Claims ### Claim 1 A method for estimating a property or environment of an optical fiber, comprising: measuring a frequency dependent electrostrictive response of an optical fiber; based on the measured frequency dependent electrostrictive response, estimating a property or environment of the optical fiber; and utilizing the property or environment for operation of a system with the optical fiber. ### Claim 2 (depends on 1) The method of claim 1, wherein the property of the optical fiber comprises one or more of optical fiber type, 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, and wherein the environment comprises one or more of optical fiber environment, optical fiber routing, and optical fiber spooling. ### Claim 3 (depends on 1) The method of claim 1, wherein the measurement of the frequency dependent electrostrictive response of the optical fiber comprises measuring the nonlinear interaction of a modulated waveform either with itself through self phase modulation or with another propagating field through cross phase modulation. ### Claim 4 (depends on 3) The method of claim 3, wherein the measuring of the frequency dependent electrostrictive response of the optical fiber further comprises monitoring strength of the nonlinear interaction as a function of modulation frequency. ### Claim 5 (depends on 3) The method of claim 3, wherein the nonlinear interaction is with an intensity modulated tone, wherein the frequency of the intensity modulated tone is based on a frequency at which the frequency dependent electrostrictive response is to be measured. ### Claim 6 (depends on 3) The method of claim 3, wherein a phase change induced on a propagated field is observed by combining the propagated field with a local oscillator on a square law detector. ### Claim 7 (depends on 3) The method of claim 3, wherein a phase change induced on a propagated field is observed through one of heterodyne detection, homodyne detection, and coherent detection using an optical hybrid. ### Claim 8 (depends on 3) The method of claim 3, wherein the measuring of the frequency dependent electrostrictive response of the optical fiber further comprises comparing an observed frequency dependent electrostrictive response of the optical fiber to one or more models using an empirical fitting method. ### Claim 9 (depends on 8) The method of claim 8, further comprising modifying the one or more models based measurements of the frequency dependent electrostrictive response of the optical fiber. ### Claim 10 (depends on 3) The method of claim 3, wherein the measuring of the frequency dependent electrostrictive response of the optical fiber further comprises observing the nonlinear interaction through noise correlation on modulated symbols of a waveform propagated through the optical fiber. ### Claim 11 An assembly for estimating a property or environment of an optical fiber, comprising: a measuring mechanism for measuring a frequency dependent electrostrictive response of an optical fiber; an estimation algorithm for, based on the measured frequency dependent electrostrictive response, estimating a property or environment of the optical fiber; and a configuration algorithm to utilize the property or environment for operation of a system with the optical fiber. ### Claim 12 (depends on 11) The assembly of claim 11, wherein the measuring mechanism comprises: a first amplifier and a second amplifier disposed at opposed ends of a fiber span carrying a channel; one or more lasers operable for generating an intensity modulated tone and injecting it into the channel at the first amplifier and generating a local oscillator that is combined with the intensity modulated tone extracted at the second amplifier; and a photodiode operable for receiving the intensity modulated tone and the local oscillator; wherein phase changes detected at the photodiode are in part attributable to nonlinear effects associated with the frequency dependent electrostrictive response of the fiber span. ### Claim 13 (depends on 12) The assembly of claim 12, wherein the fiber span comprises a compensated link comprising a span of positive dispersion fiber and a span of negative dispersion fiber. ### Claim 14 (depends on 11) The assembly of claim 11, wherein the measuring mechanism comprises: a first amplifier and a second amplifier disposed at opposed ends of a fiber span carrying a channel; a laser operable for generating an intensity modulated tone and injecting it into the channel at the first amplifier, wherein the intensity modulated tone is extracted at the second amplifier; and a homodyne square law detector operable for receiving the intensity modulated tone after it is extracted at the second amplifier; wherein phase changes detected at the homodyne square law detector are in part attributable to nonlinear effects associated with the frequency dependent electrostrictive response of the fiber span. ### Claim 15 (depends on 14) The assembly of claim 14, wherein the fiber span comprises a compensated link comprising a span of positive dispersion fiber and a span of negative dispersion fiber. ### Claim 16 (depends on 11) The assembly of claim 11, wherein the measuring mechanism comprises: an intensity modulated pump waveform propagating at a first channel wavelength on the optical fiber; and a probe waveform propagating at a second channel wavelength adjacent to the first channel wavelength on the optical fiber; wherein the first channel wavelength and the second channel wavelength experience cross phase modulation and the intensity modulated pump waveform induces correlated phase noise on the probe waveform that oscillates with the period of the intensity modulated pump waveform; and wherein a measured of phase noise as a function of tone frequency provides a measure of the frequency dependent electrostrictive response of the optical fiber. ### Claim 17 (depends on 16) The assembly of claim 16, wherein the optical fiber comprises multiple spans. ### Claim 18 (depends on 17) The assembly of claim 17, wherein the intensity modulated pump waveform is blocked between adjacent spans. ### Claim 19 (depends on 17) The assembly of claim 17, wherein different pump and or probe waveforms are utilized for different spans. ### Claim 20 A method of reducing uncertainty in the estimate of a measured fiber property of an optical fiber, comprising: estimating a property of the optical fiber via electrostriction; combining the estimated property with one or more additional estimates of the estimated property obtained through independent measurement; and utilizing the combined estimated for operation of a system with the optical fiber.