Optical systems and devices are provided that include or facilitate the ability
to provide early detection of the failure of an optical transmitter such as a laser.
Such detection may be made with reference to various aspects of the operation and
performance of the optical transmitter. For example, some of the optical systems
and devices employ wavelength shift information to make determinations concerning
potential failure of an optical transmitter. Other optical systems and devices
use information concerning the efficiency with which an incoming pump current is
converted into the ballast laser signal changes to make determinations concerning
potential failure of an optical transmitter.
