(FILE No. A2-1) TO MEASURE NFP OF SMF (Single-mode optical fiber) FOR OPTICAL COMMUNICATION USING 1550nm LD LIGHT SOURCE
Measurement method of SMF beam width by NIR NFP measurement is shown below. As the light source, 1550nm LD light source is used. As NFP measurement system, Synos' sophisticated optical beam NFP measurement optics / M-Scope type S, InGaAs high sensitivity NIR detector / ISA041, NIR objective lens / M-Plan Apo NIR 100x, are selected and arranged.
MEASUREMENT SYSTEM BLOCK DIAGRAM
MEASUREMENT SYSTEM COMPONENT
- Optical beam NFP measurement system for NIR region
- Light source (latest model)
- Sophisticated optical beam NFP measurement optics / M-Scope type S
- 2x intermediate lens MS-OP016-RL2
- Objective lens
- Detector (latest model)
- Optical beam analysis module (latest model)
Result of SMF NFP measurement, using 1550nm LD light source, is shown as left-hand image.
- Vertical 10.370um / Horizontal 10.406um（1/e2 width）
- Measurement condition
- Total magnification：200x（objective lens : 100x, intermediate lens 2x)
- Pixel resolution：0.15um
- Dark current calibration：done
- Image integration：4 frames
POINTS OF SYSTEM SELECTION
- Optics selection
- As measurement optics, Synos' optical beam NFP measurement optics / M-Scope type S is selected. Furthermore, 2x intermediate lens port is selected because the core diameter of SMF is very small (approx. 10umφ). As the result of this optics selection, real observation view is approx. 48um x 38.4um, and pixel resolution is approx. 0.15um.
- Detector selection
- As imaging detector, Synos' InGaAs high sensitivity NIR detector / ISA041 is selected, because of having high sensitivity in NIR region, good gamma characteristic, good durability against input light, etc.
- Objective lens selection
- As measurement wavelength is around 1550nm range, NIR type objective lens is selected. The reason is that NIR type objective lens has higher transmittance in NIR range than normal lens, and chromatic aberration collection is done in NIR range, etc.