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IM AQ6376E-02EN
3.8 Types of Optical Fibers That Can Be Used with
This Instrument
Types of Optical Fibers
The instrument can use single mode optical fibers with core diameters of 5 to 9.5 μm, and
multimode (GI) optical fibers with core diameters of 50 and 62.5 μm. Functions may be limited or
restricted depending on which type of optical fiber is used. The table below shows which of the
typical types of fiber may be used and the limitations on their use.
• Limitations on Wavelength Resolution
The maximum wavelength resolution for the instrument is 0.1 nm, which is only obtainable when
using a single-mode optical fiber with a core diameter of 9.5 μm or less. As shown in Table, the
maximum wavelength resolution decreases when optical fibers with thicker core diameters are
used.
Setting a resolution value finer than those shown in the table below will simply result in an
inaccurate measurement level without improving resolution.
Optical fibers with a thick core diameter are especially useful for inputting spatial light for
measurement, but they have poor resolution.
Choose the best type of optical fiber for your particular application.
Note that the instrument is designed for input through optical fiber only. It will not work with
inputs that do not pass through optical fiber, such as direct input of a gas laser beam to the
optical input connector, or bonding an LED to the optical input connector. It is important to note
that optical spectrum measurements taken through such inputs are completely unreliable.
For spatial light measurements, input the spatial light to the optical fiber and from the optical fiber
to the instrument. A variety of adapters are available for this purpose.
Summary of usable optical fiber types and usage limitations
Optical Fiber Type
Obtained Wavelength
Resolution (in nm)
Absolute Level
Accuracy
Type Core Diameter
SM
5
0.10
NG
SM
9.5
0.10
OK
GI
50
0.10
NG
GI
62.5
0.10
NG
SI
50
0.10
NG
SI
80
0.20
NG
SI
100
0.50
NG
SI
200
1.00
NG
SI
400
2.00
NG
SI
800
2.00
NG
