26 Chapter 3. Operation
laser mode. It is therefore preferable that these (low-frequency)
fluctuations are compensated in the piezo instead.
Adjusting the SLOW GAIN and SLOW INT will not necessarily produce
an improvement in the error signal spectrum, but when optimised
will reduce the sensitivity to acoustic perturbations and prolong the
lifetime of the lock.
Similarly, activating the double-integrator (DIP2) may improve sta-
bility by ensuring that the overall gain of the slow servo system is
higher than the fast servo at these lower frequencies. However, this
may cause the slow servo to overreact to low-frequency perturba-
tions and the double-integrator is only recommended if long-term
drifts in current are destabilising the lock.
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