N7768A Four-Channel Multimode Optical Attenuator

• Miniature bulk optics for best transfer of modal distribution
• Built-in power monitoring for accurate power setting and stabilizing
• Wavelength range: 800 – 1370 nm
• Attenuation range: 0 to 35 dB
• Relative power monitor uncertainty: ±0.1 dB + 300 pW
• Settling time: typ. 200 ms
• Transition speed: selectable from 0.1 to 80 and 1000 dB/s
• Optical path blocking: typ. >60 dB

Optical attenuator instruments are used to flexibly control optical signal power levels in test setups. A primary application is determining optical receiver sensitivity by measuring the BER vs. input signal power. The N7766A and N7768A provide 2 or 4 attenuator channels respectively for multimode fiber setups and are available with either 50 µm, 62.5 µm or 80 µm fiber ports. The output power is monitored, especially to allow accurate and stable power setting independent of the input power. Convenient offset parameters allow the set power to correspond to the signal after other optical components in the setup path.