  We present a painless, almost-free upgrade to present extended cavity diode
lasers (ECDLs), which improves the long term mode-hop free performance by
stabilizing the resonance of the internal cavity to the external cavity. This
stabilization is based on the observation that the frequency or amplitude noise
of the ECDL is lowest at the optimum laser diode temperature or injection
current. Thus, keeping the diode current at the level where the noise is lowest
ensures mode-hop free operation within one of the stable regions of the mode
chart, even if these should drift due to external influences. This method can
be applied directly to existing laser systems without modifying the optical
setup. We demonstrate the method in two ECDLs stabilized to vapor cells at 852
nm and 895 nm wavelength. We achieve long term mode-hop free operation and low
noise at low power consumption, even with an inexpensive non-antireflection
coated diode.
