Editing Cutback technique (section)

==Procedure==
The measurement technique consists of:
#performing the desired measurements on a long length of the fiber under test,
#cutting the fiber under test at a point near the launching end,
#repeating the measurements on the short length of fiber, and
#subtracting the results obtained on the short length to determine the results for the residual long length.

The cut should be made to retain 1&nbsp;meter or more of the fiber, in order to establish [[equilibrium mode distribution]] conditions for the second measurement. In a [[multimode fiber]], the lack of an equilibrium mode distribution could introduce errors in the measurement due to output coupling effects. In a [[single-mode fiber]], measuring a shorter cutback fiber could result in significant transmission of cladding modes (light carried in the cladding rather than the core of the optical fiber), distorting the measurement. The errors introduced will result in conservative results (''i.e.'', higher transmission losses and lower bandwidths) than would be realized under equilibrium conditions.