OS1 SMF cables are compliant with the specifications of ITU-T G.652, including ITU-T G.652A and ITU-T G.652B standards (conventional), ITU-T G.652C and G.652D standards (low-water-peak). However, OS2 SMF fiber cables are only compliant with ITU-T G.652C or ITU-T G.652D standards that are specifically applied to the low-water-peak fibers. These low-water-peak fibers are usually used for CWDM (Coarse Wavelength Division Multiplexing) applications. A new standard—G.657.A1 standard has published for bend-insensitive SMF cables for optimized performance and cost balance, some of the OS2 SMF fiber cables are accord with this standard.
Embedded in a heavy polymer jacket, the OS1 cable is suitable for tight-buffered construction of indoor applications. For indoor applications, the jacketed fiber is generally enclosed, with a bundle of flexible fibrous polymer strength members like aramid in a lightweight plastic cover to form a simple cable. Whereas the OS2 cable is predominantly of a loose-tube construction, which is more appropriate for outdoor cases. A much more robust cable construction is required when deploying in some strenuous environments. The OS2 SMF is laid helically into semi-rigid tubes, allowing the cable to stretch without stretching the fiber itself in order to protect the fiber from tension.
The attenuation of an OS1 fiber cable is higher than an OS2 fiber cable. Typically speaking, the maximum attenuation of OS1 is 1.0db/km for 1310nm and 1550nm, while the numerical value of OS2 is 0.4db/km for 1310nm and 1550nm. Consequently, the maximum transmission distance of OS1 single mode fiber is 10 km, while the maximum transmission distance of OS2 single mode fiber can reach up to 200 km. Both OS1 and OS2 single mode fibers will allow speeds of 1 to 10GbE with varied transmission distances. Furthermore, the OS2 type of single mode fiber optic cable can be applied for 40G/100G Ethernet connections.
The specification table below will present the differences between OS1 and OS2 clearly.
|ITU-T G.652C/G.657.A1 (part)