Characterization of Space-Division Multiplexing Systems using a Swept-Wavelength Interferometer

Characterization of a Fiber-Coupled 36-Core 3-Mode Photonic Lantern Spatial Multiplexer

“…Fewmode fibers (FMFs) supporting multiple spatial modes allow transmission of a number of channels on an orthogonal combination of modes of the FMF, at the cost of requiring multiple-input multiple-output (MIMO) equalization to remove the mode mixing and scrambling occurring in the fiber and during mode (de-)multiplexing [2][3][4]. Multi-core fibers (MCFs) reduce the footprint and increase capacity at the cost of introducing inter-core crosstalk [1].…”

Few-mode fiber, splice and SDM component characterization by spatially-diverse optical vector network analysis

“…To measure the full transfer function matrix of a multiport, space division multiplexing (sdm) system or component, the scheme may be extended to form a spatially diverse optical vector network analyzer (sdm-ovna) [22,25,27]. This section presents the setup and principle of operation of an sdm-ovna for the analysis of an sdm system or component with N × N ports in section 2.1 and discusses the digital signal processing (dsp) for measurement of the impulse response, complex transfer function and linear parameters (such as insertion loss (il), modedependent loss (mdl), differential modal group delay (dmd) and mode coupling) of the system or component in section 2.2.…”

“…dmd may be derived fromH(ω) by means of principle state of polarization analysis [11,21,29] where the principle delays are approximated by the eigenvalues ofH(ω + ∆ω)H −1 (ω) or by directly analyzing the impulse responsesh k ,l (t) [22,25,30]. In the latter case, distinct peaks for different mode groups h k ,l (t) will be observed and dmd may be derived from the ratio of their respective spacing and the fiber length.…”

“…Analysis of the impulse response is demonstrated in detail in section 3.2. Finally, mode coupling may also be seen from analysis of theh k ,l (t), where distributed mode coupling along the fiber will appear as plateaus between the peaks of the respective modes and mode coupling at discrete points generate additional peaks in the temporal response [22,25,30].…”

“…More recently, spatially diverse optical vector network analyzer (sdm-ovna) setups have been introduced, allowing measurement of the temporal and spectral response of fmfs [11,22], as well as characterization of sdm system components [14,23,24]. The mode-mixing at fiber splices and their impact on system il and mdl was investigated by the authors in [17,25], based on analysis of the impulse response and comparison of measurements with different splices.…”