Fiber Distance Planning for 10G, 25G & 100G
Optical Engineering Guide
Calculating maximum reach for high-speed optics: 10GBASE-LR (10km), 10GBASE-ER (40km), 10GBASE-ZR (80km), and 100G QSFP28 LR4.
Technical Attribute Comparison Matrix
10G SR (850nm MM)300 metersRequires OM3/OM4 multimode
10G LR (1310nm SM)10 kilometersStandard single-mode OS2
10G ER (1550nm SM)40 kilometersHigh-power laser; verify minimum path attenuation
10G ZR (1550nm SM)80 kilometersRequires optical attenuators if tested on short bench fibers
100G CWDM4 / LR42km to 10km4-wavelength optical multiplexing inside QSFP28 form factor
Pre-Procurement Checklist
Always test long-range ER/ZR optics with optical attenuators before bench testing to avoid burning the receiver photodiode.
Account for 0.35 dB/km loss at 1310nm and 0.22 dB/km loss at 1550nm.
Factor in chromatic dispersion limits on long-distance links over 40km.