Development of an electro-optic sampling system at LNE

We present the development of an electro-optic sampling system for the calibration of an electrical impulse response standard photodiode. The configuration uses a 100 μm thick LiTaO₃ or GaAs electro-optic crystal placed above a coplanar waveguide supported by a glass substrate. Transverse dimensions of the coplanar waveguide are adjusted in order to obtain a good impedance match between the free sections of the coplanar waveguide and the section covered by the electro-optic crystal. The electro-optic sampling system uses a mode-locked fiber laser producing a train of pulses at 1550 nm with pulse duration of about 90 fs.