Keysight Technologies N77 Series User Manual page 11

Getting Started 1
The Keysight N7766A and the Keysight N7768A are optical attenuators
for multimode fibers with two or four attenuator channels repectively.
Both multimode attenuators are available with 50 micro-meter, 62.5
micro-meter, or 80 micro-meter-core multimode fibre.
The N7766A and N7768A are 2 and 4 channel multimode fiber
attenuators that are optimized for quick power setting and preservation
of the input modal power distribution.
The attenuators are designed to attenuate and control the power of light
in optical fibers. They allow you to accurately and repeatably set the
attenuation factor or power level manually using the Viewer software,
or using the programming interface.
The attenuators include power control functionality that allow you to
set the output power level of the attenuator. When power control mode
is enabled, the module automatically corrects for power changes at the
input so that the output power level you set is maintained.
Figure 1 Optical Attenuators with Power Control
The one rack unit (1U half-rack high) instrument can be operated alone
or with other units, controlled over LAN, USB, or GPIB.
These attenuators and power meters are fully compatible with setups
and programs developed using the Keysight 8157x modular
attenuators and basic 8163x optical power meter commands, not
including logging functionality.
Modal Fidelity for Multimode Fiber Systems
Signals in multimode fibers are distributed over a range of mode groups
that can have different loss and delay in a link. For dependable
multimode transceiver testing, the instrument used to set the power
level should not change this modal distribution. The bulk-optic filter and
collimated beam path of Keysight multimode attenuators are designed
to assure homogeneous attenuation of all input modes.
Keysight N77xx Series 11