光計測用光学機器と光計測システムのシナジーオプトシステムズ

(FILE No. A2-2) TO MEASURE NFP OF MMF (multi-mode optical fiber) USING 850nm LD LIGHT SOURCE

OUTLINE

Measurement method of near field pattern of MMF (multi-mode optical fiber) by NFP measurement is shown below. As the light source, 850nm LD light source is used. As NFP measurement system, Synos' sophisticated optical beam NFP measurement optics / M-Scope type S, high resolution digital CCD detector / ISA011, objective lens / M-Plan Apo 20x, are selected and arranged.

MEASUREMENT SYSTEM

MEASUREMENT SYSTEM BLOCK DIAGRAM

MEASUREMENT SYSTEM COMPONENT

MEASUREMENT RESULT

Result of MMF NFP measurement, using 850nm LD light source, is shown as left-hand image.

  • Beam width
    • Vertical 52.342um / Horizontal 52.940um(1/e2 width)
  • Measurement condition
    • Total magnification:20x (objective lens : 20x)
    • Pixel resolution:0.2325um
    • Dark current calibration:done
    • Image integration:8 frames

In addition, from the acqcuired MMF NFP image, encircled flux analysis is done as shown in left-hand image.

  • EF graph
    • refer to left-hand image
  • condition
    • center:gravity of area
    • Setting of analysis area criteria:30um
    • Setting of analysis radius coefficient:1.15
    • Setting of sampling pitch:0.1um
    • Background calibration:done (coefficient 1.2)

POINTS OF SYSTEM SELECTION

  • Optics selection
    • As measurement optics, Synos' optical beam NFP measurement optics / M-Scope type S is selected. As objective lens, 20x is selected. As the result of this optics selection, real observation view is approx. 320um x 240um, and pixel resolution is approx. 0.23um.
  • Detector selection
    • As imaging detector, Synos' high resolution digital CCD detector / ISA011 is selected, because of having high resolution and sensitivity in 850nm region, good gamma characteristic, good durability against input light, etc.
  • Objective lens selection
    • As measurement wavelength is around 850nm range, standard type objective lens is selected.

ADDITIONAL INFORMATION