Numerical Aperture Conversion Fiber

The 735384 NA Conversion Fiber is the accessory for the AQ6360/AQ6370 series optical spectrum analyzer.
The NA Conversion Fiber improves the stability of the optical level measurement of the optical spectrum analyzer.

What is the numerical aperture of an optical fiber?

What is meant by 'numerical aperture?'  The numerical aperture is the range of angles at which an optical fiber can transmit its beam. It's related to refraction and the beam spread angle.

Numerical Aperture Formula

Numerical Aperture (NA)=n×sin(µ) or n×sin(α)

Role of NA Conversion Fiber

The NA Conversion Fiber is only applicable to the free space optical input structure on the AQ6360 and AQ6370 series optical spectrum analyzer.
By connecting a GI 50 or GI 62.5 optical fiber with a relatively large NA to the NA Conversion Fiber, the NA Conversion Fiber reduces the loss that occurs at the input and improves the measurement dynamic range during passive device measurements and the stability of optical level measurements during active device measurements.

Connect this product to the optical input of the applicable optical spectrum analyzer.



Product Code 735384-A001 735384-A002
Applicable Fiber MM (GI 50/125) MM (GI 50/125, 62.5/125)
NA Conversion Ratio Approx. 1/3
Applicable OSA Models All versions of AQ6360, AQ6370, AQ6373, AQ6374, AQ6375, and AQ6376 (only up to 1700 nm)


  • The stability of measurement results depend on the operating environment.
  • If the wavelength resolution of the optical spectrum analyzer is set smaller than 0.05 nm when using the NA converted fiber, the measurement results may become unstable.
     Setting the wavelength resolution to a larger wavelength resolution, such as 0.1 nm or 0.2 nm, gradually improves the stability of the measurement results.
  • When using GI62.5 and GI50 multimode optical fibers coupled to NA converted fibers, it is recommended to set the wavelength resolution of the optical spectrum analyzer to 0.2 nm or higher.


Instruction Manuals

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