You don't just pick an attenuator and plug it in and you're done. If you select a small one, the light receiving will still be near the overload point; if you select a large one, the link margin will be eaten up in vain, and the jumper may fall below the sensitivity due to aging in the future. The correct sequence is to first determine the target light collection, and then infer the attenuation value from the link budget.

Reverse target closing: subtraction in the middle of the interval

The target value is generally 6 to 10dB below the overload point and more than 3dB above the sensitivity. For example: The measured receiving end is -2dBm, the module overload point is -3dBm, and the sensitivity is -20dBm. To reduce the receiving light to -8dBm, about 6dB attenuation is needed. Take the whole 6dB, or use a combination of 2dB and 5dB to approach the target value.

Each of the three structures has its own access location.

  • The jumper type comes with two sections of pigtails, suitable for temporary testing and surface installation in the cabinet;
  • Flange type screws directly onto the adapter or port panel, suitable for long-term fixation within the ODF;
  • The modular card is installed in the card slot of the patch panel, suitable for batch design, and its appearance is consistent with that of ordinary adapter ports;
  • Each additional connection point will cause an additional insertion loss of about 0.3dB. The more levels, the better; if the flange type is directly screwed to the optical port on the equipment side, it will affect the normal plugging and unplugging of the jumper. It is recommended to fix it on the wiring side.

Two details that are easily overlooked: tolerance and wavelength flatness

The nominal tolerance of conventional fixed attenuators is about plus or minus 0.5dB, and some gears have slight deviations at different wavelengths. For 1310 and 1550 dual-wavelength systems, it is recommended to check the two wavelength points separately, or directly select the flat wavelength type. withSC-SC single mode single core jumperJust indicate the flange type when purchasing in the same batch; if you are not sure about the gear, you can send the link list to EB-LINK technical support for calculation, call 0755-83179002.