This application note covers theory of laser modulation methods,
time-resolved chirp (TRC) measurement methods, and applications
of TRC measurement data to predict laser performance in a trans-
mission system. Also covered are the details of making laser chirp
measurements using the Agilent Technologies 86146B Option TRC
software.
Understanding the effects of chirp on the transmission of signals is
of great importance to the system designer. Chirp can have two sep-
arate detrimental outcomes in a typical transmission system. The
first is that the chirp can interact with the fiber dispersion to create
a power penalty, which ultimately limits the number of channels or
the distance over which the signal can propagate in today’s WDM
systems.? The second is that chirp can broaden the transmitted spec-
trum limiting the channel spacing by interfering with adjacent chan-
nels even in a short-haul ultra-dense WDM environment.