EXFO T100S-HP Essential, User Manual, Page: 46 / 70

Using the Auxiliary Inputs and Outputs
46 T100S-HP User Guide
8.1.2 Implementing High Frequency Intensity Modulation
Subject The HF Mod input allows you to increase the total diode current by applying voltage to
the HF Mod SMA connector.
A valid high frequency modulation signal applied to the SMA port can range from 30 KHz
up to 200 MHz.
Before Starting
Procedure 1. Connect an external high frequency modulation source to the HF Mod. SMA
connector, as shown in the following Figure 10, p. 46 .
Make sure to use a 50 Ω coaxial cord to connect your HF generator to the 50 input
SMA connector.
Figure 10: High frequency modulation setup
2. Use High Frequency Modulation:
Important
Before implementing external modulation via HF Mod input connector, make
sure the system’s active cavity control is disabled (see section Disabling/
Enabling Active Cavity Control, p. 35 ).
Warning
Since the HF Mod SMA input is directly connected to the laser diode
chip via a 50 Ω resistor, you must ensure that the input voltage on the HF
Mod connector is such that the following conditions are always met, to
avoid the destruction of the diode:
• The diode laser is forward biased.
• The current flowing through the diode is lower than the maximum
admissible current (I
max
) indicated in the system acceptance test
report.
T100S-HP Laser Diode Source
R
internal
50
Ω
Waveform Generator
50
Ω
I
bias
Polarization Current
I
in
I
diode
V
in
Coaxial Cord
50
Ω
HF Mod.
SMA Connector