THORLABS ULN15 Series, User Manual, Page: 8 / 24

Ultra-Low Noise Laser Chapter 3: Description
Page 6 QTN039956-D02
Figure 2 Typical ULN spectrum at single mode operation with
an operating point above 100 mW. T
CHIP
and T
FBG
are 25 °C.
Current adjustment provides only a limited tuning range before the ULN laser hops to a new mode, as shown in
Figure 3. The actual tuning is smoother than shown; these data are impacted by the 4 pm sampling resolution of
this measurement. Longer-range tuning can only be achieved by adjustment of the FBG temperature. This
changes the center wavelength of the FBG’s resonant frequency.
Figure 3 LI plot overlaid with current-tuning characteristics. Note that the optical spectrum analyzer
used in this measurement was set to a sampling resolution of 4 pm; the actual tuning is smoother
than shown here. This is a C-configuration device
operated at the optimal ΔT, which is the
difference between T
FBG
and T
CHIP
.
1548 1549 1550 1551 1552
-65
-55
-45
-35
-25
-15
-5
5
15
Typical Optical Spectrum
Amp
litu
de (
dB)
Wavelength (nm)
0 100 200 300 400 500 600 700 800 900
0
20
40
60
80
100
120
140
160
180
Decreasing Current
Center Wavelength
Laser Output Characteristics vs. Current
Power (mW)
Current (mA)
1549.91
1549.92
1549.93
1549.94
Ce
nter Wave
leng
th
(nm)