Embodiments of the present invention generally relate to the field of fiber optics, and more specifically to apparatuses, methods, and/or systems associated with testing fiber optic transmitters. In an embodiment, the present invention is an apparatus comprising a laser optimized multimode fiber having near minimally compliant effective modal bandwidth, near maximum channel length, and ?-profile that produces an R-MMF DMD slope.

The invention concerns a method of characterizing a multimode optical fiber link comprising a light source and a multimode fiber, which comprises: a step (170) of characterizing the multimode fiber using a measurement of the Dispersion Modal Delay (DMD) and delivering fiber characteristic data; a step (171) of characterizing the light source by at least three source characteristic curves showing three parameters of the source as a function of a fiber radius r and obtained by a technique similar to the DMD measurement; a step (173) of computing an Effective Bandwidth (EB) of the link, comprising calculating (172) a transfer function using both the fiber characteristic data and each of said source characteristic curves.

Methods for estimating the Effective Modal Bandwidth (EMB) of laser optimized Multimode Fiber (MMF) at a specified wavelength, .sub.S, based on the measured EMB at a first reference measurement wavelength, .sub.M. In these methods the Differential Mode Delay (DMD) of a MMF is measured and the Effective Modal Bandwidth (EMB) is computed at a first measurement wavelength. By extracting signal features such as centroids, peak power, pulse widths, and skews, as described in this disclosure, the EMB can be estimated at a second specified wavelength with different degrees of accuracy. The first method estimates the EMB at the second specified wavelength based on measurements at the reference wavelength. The second method predicts if the EMB at the second specified wavelength is equal or greater than a specified bandwidth limit.

The invention relates to a method of measuring time delays with respect to differential mode delay of a multi-mode fiber or a few-mode fiber for at least two different wavelengths. The time delays for each wavelength are measured before the single mode fiber is translated to a next radial offset.

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 r.sub.offset, 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 (EMB.sub.c.sub.1; EMB.sub.c.sub.2) 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 comparing step.

A PV vector measuring apparatus includes: a light source 101configured to output probe light; a polarization switch 102 that can freely set a state of polarization of input light; a polarimeter 104; a PV-vector calculating device 105; and a rectangular wave generator 106. The polarization switch alternately switches between two orthogonal states of polarization in accordance with a rectangular wave modulation signal output from the rectangular wave generator. Output light from the polarization switch is input to a measurement object 103. The polarimeter 104 measures time dependency of an SOP vector of output light output from the measurement object. The PV-vector calculating device calculates a characteristic vector, which expresses a rate of polarization change in the measurement object, from the time dependency of the SOP vector.

An optical amplifier assembly for determining a parameter of an optical fibre configured to amplify an optical signal being propagated therethrough, the assembly comprising: at least one amplifier pump light source assembly configured to transmit light at a plurality of wavelengths into the optical fibre; a receiver configured to receive light that has propagated through at least part of the optical fibre; and a processor configured to determine the parameter of the optical fibre based on the received light.

Systems and methods for optical fiber characterization using a nonlinear measurement of shaped Amplified Spontaneous Emission (ASE) transmitted over the optical fiber are provided. A method includes receiving an ASE signal on an optical fiber, wherein the ASE signal is transmitted from an ASE source connected to the optical fiber and the ASE signal includes a spectral shape at an input of the optical fiber; measuring a broadened spectral shape of the received ASE signal where the broadened spectral shape is different from the spectral shape at the input and broadened due to propagation of the ASE signal over the optical fiber; and determining one or more parameters of the optical fiber based on the broadened spectral shape of the received ASE signal.

A PV vector measuring apparatus includes: a light source 101configured to output probe light; a polarization switch 102 that can freely set a state of polarization of input light; a polarimeter 104; a PV-vector calculating device 105; and a rectangular wave generator 106. The polarization switch alternately switches between two orthogonal states of polarization in accordance with a rectangular wave modulation signal output from the rectangular wave generator. Output light from the polarization switch is input to a measurement object 103. The polarimeter 104 measures time dependency of an SOP vector of output light output from the measurement object. The PV-vector calculating device calculates a characteristic vector, which expresses a rate of polarization change in the measurement object, from the time dependency of the SOP vector.

A wide-band optical frequency comb is provided to estimate an optical phase shift induced in a dispersive material. In contrast to the conventional techniques that rely on a single tunable laser for extracting the dispersion parameter at different frequencies, the wide-band optical frequency comb uses multiple comb lines for simultaneously evaluating the dispersion induced phase shifts in different frequencies. Since the frequency response of the dispersive material is a phase function, a phase associated with each comb line passed through the material represents a discrete measure of the material frequency response.