Starting Download..
save Save

Is there an electrical extender cable available for the 8162xA/B optical heads?

The 8162xA/B optical heads work with the 81618A single and 81619A dual channel interface module. The interface modules slide into the 8163 / 8164 / 8166 mainframes. There is an electrical cable at the optical head to plug into the interface module. The standard cable is 48". If this is not long enough, an electrical extender cable is available. The model number of this cable, with a length of 4 meters, is 81624CE.

 

Keysight Technologies offers several different optical heads, some using InGaAs as the sensing element, others using Ge as the sensing element.

The relative uncertainty due to polarization is less for InGaAs based optical heads than for Ge based optical heads. If the best PDL measurement is needed, please consider the InGaAs based optical heads. Please realize that the InGaAs based optical power sensors can be used as well for PDL measurements.

An important difference between Ge and InGaAs is the shape of the spectral responsivity curves. InGaAs tends to be very flat across the 1500 and 1600nm bands. Ge reaches a peak at about 1530nm and drops very steeply at longer wavelengths. Keysight Technologies calibrates all heads over wavelength, storing the values in EEPROM in the head. When the user enters the wavelength of the source being measured, the calibration factor for that wavelength is called from the EEPROM. If the user enters the correct wavelength of the source being measured, the Ge and InGaAs have equivalent accuracies.

A problem occurs when the wrong wavelength is entered. In the 1550nm area the error for InGaAs is very small, even for a 5nm wavelength setting error. For Ge the error will be quite large. These errors are for absolute power measurements (in Watts or dBm's). Note that this is not an issue for relative measurements, such as insertion loss (in dB's) as long as the source wavelength is stable.

Another issue for the Ge is when measuring broadband light, such as ASE from an optical amplifier. The Ge will not measure all wavelengths equally.

In summary, the Ge optical heads are a good choice for absolute power measurements when the source wavelength is well known and for relative power measurements such as insertion loss.

In DWDM systems, the wavelengths of the DFB transmitters must be well known, so using Ge is usually not a problem, as long as the known wavelength is entered correctly.

Was this helpful?


Didn't find what you're looking for?