Method of classifying a graded-index multimode optical fiber
AssigneeDraka Comteq B.V.
InventorsAsghar Gholami, Denis Molin, Pierre Sillard, Yves Lumineau
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Abstract
A method of classifying a graded-index multimode optical fiber includes taking a series of individual measurements at a single wavelength, and using the measurements to characterize the departure of the multimode optical fiber's actual index profile from the corresponding nominal index profile. The measurements, coupled with intermodal dispersion or EMB measurement, may be used to predict the approximate transmission properties of the optical fiber at wavelengths other than the measurement wavelength.
Claims25
A method of classifying a graded-index multimode optical fiber, comprising:
- (i) injecting into the core of a multimode optical fiber a light pulse having a predefined wavelength, wherein the light pulse is injected at a radial offset from the center of the optical fiber's inlet face;
- (ii) detecting the light pulse at the optical fiber's outlet face to determine the time characteristic of the light pulse after propagation through the optical fiber from the optical fiber's inlet face to the optical fiber's outlet face;
- and
- (iii) repeating steps (i) and (ii) for a plurality of radial-offset values;
- and
- (iv) determining the radial offset bandwidth (ROB) as a function of the radial offset.
A method of evaluating and selecting a multimode optical fiber, comprising:
- providing a multimode optical fiber having a core, an inlet face, and an outlet face;
- injecting into the multimode optical fiber a light pulse of a testing wavelength, the light pulse being injected at a radial offset from the center of the multimode optical fiber's inlet face;
- detecting the light pulse at the multimode optical fiber's outlet face to measure the time characteristic of the light pulse after propagation through the multimode optical fiber;
- repeating for a plurality of radial-offset values the steps of injecting a light pulse and detecting the light pulse;
- determining, at the testing wavelength, the effective modal bandwidth (EMB) of the multimode optical fiber via the measured time characteristics of the light pulse;
- assessing if the multimode optical fiber's determined effective modal bandwidth is within a predetermined range;
- determining the multimode optical fiber's radial offset bandwidth (ROB) as a function of the radial offset via the measured time characteristics of the light pulse;
- and
- assessing if the multimode optical fiber's determined radial offset bandwidth meets or exceeds a threshold value for all radial-offset values between 0 and R1, wherein R1 is less than or equal to the core radius of the multimode optical fiber.
A method of classifying a graded-index multimode optical fiber, comprising:
- (i) injecting into the core of a multimode optical fiber a light pulse having a predefined wavelength, wherein the light pulse is injected at a radial offset from the center of the optical fiber's inlet face;
- (ii) detecting the light pulse at the optical fiber's outlet face to determine the time characteristic of the light pulse after propagation through the optical fiber from the optical fiber's inlet face to the optical fiber's outlet face;
- and
- (iii) repeating steps (i) and (ii) for a plurality of radial-offset values;
- and
- (iv) determining the radial offset bandwidth (ROB) as a function of the radial offset;
- and
- (v) determining whether the radial offset bandwidth as a function of the radial offset values determined in step (iv) is greater than or equal to 6000 MHz·km for all radial-offset values between about 0 and R1, where R1 is about 70 percent of the radius of the optical fiber's core.
Dependencies are inferred from the claim text.