USER MANUAL
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APPENDIX E
MOPA FIBER LASER
LASER MARKER OPERATIONS
The Arex™ A20-X6X is a very flexible laser marker based on a master oscillator power
amplifier (MOPA) architecture, that allows the user for a wide selection of pulse profiles
and pulse repetition frequencies.
Depending on the Pulse Profile selection and pulse Frequency the laser will generate
pulses with stable output energy/peak power or stable laser average power.
The following picture illustrates the pulse peak power and laser average power depen-
dence on the frequency, for the entire operating frequency range.
Figure 1: Typical average power (dash line) and peak power (solid line) dependence on the
frequency for the 8 ns the pulse profile
As shown, when the laser is operated with Frequency above the pulse transition Fre-
quency (fT) (typically 200 kHz for the 8 ns pulse profile) the average power (dash lines)
remains constant while the pulse energy/peak power (solid lines) will change. This is the
more common operating region for most applications. Datalogic designates this region
as the “Constant Average Power Region”.
A characteristic of the Datalogic Arex™ A20-X6X laser marker is that user is allowed to
operate the laser at pulse repetition frequencies that can be reduced down to 20kHz
and up to 500kHz (depending on Pulse profile selected). If the laser was allowed to
operate down to lower frequencies without any restriction, the pulse energy would
keep increasing until reaching non-linear thresholds that would result in laser perfor-
mance degradation or even self-destructive failure. To prevent the laser marker from
reaching these undesired conditions, while allowing the user to set the laser pulse fre-
quency freely, Datalogic implemented laser internal safety controls to allow stable pulse
peak power/energy below the transition frequency (fT).
