Yenista Optics OSICS, Руководство пользователя

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Using the OSICS SWT APC Module
OSICS User Manual 165
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12.8 Activating Coherence Control on all Connected T100 and
ECL Modules (Full-Band Mode)
Subject The OSICS SWT APC module enables you to control the Coherence Control function of all
the connected ECL and T100 modules.
The Coherence Control function induces broadening of the OSICS T100 or ECL tunable
laser linewidth. This feature is especially useful in helping reduce interferometric noise.
Coherence control consists in modulating the frequency with a pseudo-noise signal that
widens the OSICS T100 or ECL optical signal linewidth. The specified linewidth for the
OSICS T100 or ECL module is 150 kHz (typical value) as indicated in the module
specifications without coherence control. This linewidth is brought to 100 MHz when the
coherence control function is on.
The OSICS T100 and ECL modules feature a built-in modulation source used to
implement coherence control function on-board. You do not need to connect any
external modulation device to the OSICS system.
The following procedure explains how to activate the coherence control function to
produce the linewidth broadening required.
Before Starting • Set the SWT APC to Full-Band mode (see section Selecting the Operating Mode,
p. 154 ) and specify the connected modules (section Configuring the Full-Band Mode,
p. 156 ).
Procedure 1. Access the SWT APC Unit Setup menu (see section Accessing an OSICS Module Setup
Menu, p. 33 ).
2. Turn the rotary knob to put the cursor before the Coherence menu and press the
knob.
The
Coherence menu appears and the cursor points to the current setting.
Figure 121: SWT APC Unit Setup – Coherence Control menu
3. Turn the rotary knob to put the cursor before the wanted setting, and press it to
validate your selection.
The new state of the coherence control function is implemented immediately in all
the ECL and T100 modules connected to the SWT APC. The Unit Setup menu is
automatically displayed.
In the OSICS
System Status screen, the message C is displayed in the OSICS module
channel Info field if the coherence control function is currently enabled on this
module.
Main
EXIT
1 2 3 4 5 6 7 8
Unit Setup - Coherence
ESCAPE
▲
Coherence :
OFF
ON
Select a new value.