
2.4 WORKING DEFINITIONS OF CUTOFF
WAVELENGTH
2.4.1 Introduction
The cutoff wavelength of a single-mode optical fiber is the wavelength above
which only a single bound mode, the fundamental LP
01
mode, propagates. For
numerous reasons concerning transmission performance (bandwidth, multipath
interference, modal noise, etc.), it is desirable to operate fibers in the regime
where only the fundamental mode propagates. (This discussion does not address
the intentional use of multimoded fibers for short-reach applications, where as
many as 10- to 18-mode groups may be allowed to propagate at the operating
wavelength.) In this section, we discuss the theoretical ...