Yenista Optics OSICS, Руководство пользователя

Страница: 214 / 252

Using the OSICS TLS-50 Module
214 OSICS User Manual
BKR
TL
S-50
AT
N
DFB
EC
L
T100
SLD
SW
T
TLS-A
G
SW
T A
PC
MAI
N
14.5 Setting the SBS Suppression Mode
The SBS suppression mode allows you to add internal modulation to the source, to
broaden the laser line width.
You can select one of the following (both modulation types cannot be selected at the
same time):
• Amplitude Modulation (AM)
The amplitude modulation (trace tone) operates at a frequency that can be detected
by an optical receiver. The operational frequency band is within the opto RX
detectable bandwidth > 50 kHz.
AM signaling is typically used during channel commissioning to identify a specific
transmitter wavelength detected by an optical receiver.
Figure 161: TLS-50 – Amplitude Modulation
You can configure this modulation mode with the following parameters:
• The frequency of this modulation from 10 to 500 kHz ( SBS Rate , see section
Selecting the SBS Rate, p. 216 )
• The shape: sinusoidal or triangular ( SBS Waveform , see section Selecting the SBS
Waveform, p. 216 )
• The amplitude deviation is the amplitude modulation depth in % = X/Y*100%
between 0.1 and 10% ( SBS AM , see section Selecting the Amplitude Deviation,
p. 218 )
OIF standard recommendation: Sinusoidal, 100 to 200 kHz (within the optical receiver
unit detectable bandwidth).
• Frequency Modulation (FM)
Frequency modulation requires the application of a dither signal to modulate the
frequency of the laser, to broaden the effective linewidth of the laser and reduce the
effects of Stimulated Brillouin Scattering in the optical fiber, the laser is modulated
with a single frequency dither signal (triangular or sinusoidal). Ideally the frequency
(repetition rate) of the SBS dither signal must be kept within the lower kHz range.
You can configure this modulation mode with the following parameters:
• The frequency of this modulation from 10 to 100 kHz ( SBS Rate , see section
Selecting the SBS Rate, p. 216 )
• The shape: sinusoidal or triangular ( SBS Waveform , see section Selecting the SBS
Waveform, p. 216 )
X
Mean CW
Power Level
Y
Zero
Power Level