Fiber Coupled Laser Source
Chapter 7: Maximizing the Stability
Rev E, April 6, 2017
Page 11
24.3 °C, 1547.994 nm
24.4 °C, 1548.830 nm
24.5 °C, 1548.834 nm
24.7 °C, 1548.839 nm
24.9 °C, 1548.839 nm
Figure 6
Wavelength vs. Power Plots – Variation in Temperature
The five plots in Figure 6 above, show the relationship of temperature verse stability. With the drive current fixed
at 85% of maximum, the operating temperature was increased by 0.1°C per plot, starting at 24.3 °C. In the first
plot, the laser appears stable but it can be improved. As the temperature is increased to 24.4 °C the laser enters a
transition point between modes. At this temperature, the laser may mode hop resulting in erratic output. At 24.5
°C the laser has reached a stable operating point, indicated by the single narrow line width. The last two plots
(24.7 °C and 24.9 °C) show the laser passing through the optimum point and decreasing in stability and desired
output.
Some important points to note are:
This is not the only setting capable of stable operation, there are many
This combination of temperature and current may not produce stable operation with a different unit.
In both of the above examples (fixed temperature or fixed current) the instabilities are a direct result of the effect
that current or temperature has on the peak wavelength of the laser, shifting it ever so slightly into regions that do
not support good lasing.
