EXFO FLS-2600B Tunable Laser Source - Manual (Page 77)

Tunable Laser Source 69
B Trigger Option Theory
Your Tunable Laser Source features Trigger In and Out connectors. When
the trigger option is set to On, the Trigger In will wait for signals. The Trigger
Out is always active and emits a signal for each one-way pass (Continuous
mode) or step (Stepped mode) the system performs during the sweep.
The synchronization feature uses a TTL, 5 V signal. It is achieved on the
signal’s rising edge. The pulse width of the Trigger In signal must be larger
than 1 μs. The pulse width of the Trigger Out signal is 8 μs.
Trigger Option in Continuous Mode
The sweep will begin when the first synchronization signal is received at
the In port. When a pass (one way) is completed, the system waits for
another synchronization signal to move again.
If the synchronization signal arrives before the sweep is completed, it is
kept in memory to be used on the next pass. The memory keeps only one
synchronization signal on standby; if the system receives more than one
signal before the sweep is completed, only the first one will be kept.
(a) sweep start
(b) second sweep trigger
(c) trig received during the
second sweep; kept in
memory and will trigger the
third sweep
(d) trig received during the
third sweep kept in memory
and will trigger the fourth
sweep
(e) lost trig