EXFO T100S-HP Essential, Руководство пользователя, Страница: 34 / 70

Changing the Optical Output Power and Diode Current
34 T100S-HP User Guide
5.2 Switching Between Constant-Power and Constant-Current
Modes
Subject • The constant-current mode enables you to change the wavelength/frequency of the
laser while maintaining the diode current level.
• The constant-power mode enables you to change the wavelength/frequency of the
laser while maintaining the output power level. In this mode, the diode current is
automatically adjusted through a feedback loop.
The APC function key allows you to toggle between the constant-current and the
constant-power modes.
Procedure • To activate the constant-power mode, press the APC function key to turn on the APC
key LED:
The active mode is
constant-power : the laser-diode current is controlled to ensure an
optical power output equal to the P parameter.
By pressing the P function key, the system switches automatically to the constant-
power mode.
In this mode, the required power cannot be obtained, even with the maximum
allowable current. In this case:
• The current is limited to its maximum value.
• The optical power is lower than the user-set power value.
• The Lim message is displayed to the right of the current and power values.
• To activate the constant-current mode, press the APC function key to turn off the
APC key LED:
The active mode is
constant-current : the diode current level is determined by the I
parameter.
By pressing the
I function key, the system switches automatically to the constant-
current mode.