Updated on:
Apr 5, 2005


Fiber Mode Field Distribution Measurement System (MFMS)

Fiber mode field distribution measurement system
Device photo

General description

MFMS is developed for measuring the far-field pattern of optical fibers. The automatic system provides high quality measurements with good reproducibility.

Technical device characteristics

Measuring dynamic range, dB>50
Angle resolution, rad0.01
Minimal angle step, rad2.6·10-4
Scan range, rad~3
Measuring stability, %0.2
Warming-up time, min10


User-friendly software developed for MFMS allows:

  • calibrate photodiode angle position;
  • measure angle intensity distribution in far field in variable angle range and number of points;
  • vary measurement time in every point by averaging to achieve specified inaccuracy;
  • save and open measured distributions;
  • draw up to 4 traces (graphical design is provided with numerous features for convenient data viewing and analyzing);
  • perform mathematical calculation to convert angle (far field) distribution to radial (near field) one and to determine characteristic mode field diameters (1/e2, dispersion [Petermann II], microbending [Petermann I]).

Measuring examples

Checking linearity of MFD measurement system
Linearity of MFD measurement system

Left side represents angle distributions, measured with different input optical level (~10 dB from curve to curve). On the right side the curves are normalized at their maxima. Curves coincidence characterizes linearity of the measuring system in the whole dynamic range.

Angle distributions of radiation intensity in far field
Angle distributions of radiation intensity in far field,
measured at a) 1.32 mkm, b) 1.53 mkm for fiber samples:
1 - Corning SMF-28, 2 - Corning DSF, 3 - SM-179 (high NA)

Calculated near field distributions
Calculated near field distributions for specified fibers


More detailed device description can be found in russian section: Mode field measuring

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