PID lockbox

This electronic module is intended for stabilizing external cavity diode lasers to high-finesse external resonators in the research field of optical atomic standards. The device comprises two essential blocks – a fast feedback PID lockbox, and a slow PI lockbox. The lockbox allows reaching sub-Hz laser linewidths because it is built after the same schematics as used for sub-Hz stabilized linewidth laser which is described in paper by Alnis et al. in Phys. Rev. A 77, 053809 (2008). The key specifications and images of the device as well as graphs obtained during the operation are shown below.
Key specifications:

Fast feedback branch

  • 50 Ohm inverting and non-inverting inputs. Can be used as single ended or differential;
  • Input signal range ± 1V;
  • Input noise of amplifier 0.92 nV/Hz^1/2, 2.3 pA/Hz^1/2;
  • 10 MHz proportional bandwidth (-3dB);
  • Proportional gain switchable -30…+20 dB in 10 dB steps and using fine adjustment;
  • Input to output delay time 13 ns.

Slow feedback branch

  • Input impedance 10 kOhm;
  • Input amplifier noise 3 nV/Hz^1/2;
  • Low input offset drift 0.2 μV/degC;
  • Proportional bandwidth 70 kHz(-3dB);
  • Integrator low frequency voltage gain 70 dB;
  • Output range ± 12 V. Output current ca 10 mA;