1.5 µm - optical frequency standard iodine stabilized in the 10-15 range for space-mission applications

International audienceWe report on the development of an optical frequency standard (OFS) operating in the C-Telecom band, stabilized in the 10-15 range, using Doppler-free spectroscopy of iodine hyperfine line around 514 nm. To bridge the frequency gap between infrared (IR) and green domains, we operate an efficient frequency tripling process of the IR laser diode, with two cascaded nonlinear Lithium Niobate crystals. We have implemented an original optical arrangement which allows a high efficiency optical power conversion (P  P), yielding to 300 mW at 514 nm. The generated green optical power is 20 times higher than the optical level required for the frequency stabilization purpose. We have demonstrated a residual frequency instability of 4.8 x 10-14 τ-1/2 with a minimum value of 6 x 10-15 conferred to a butterfly laser diode emitting at 1542 nm. A novel demonstrator-fully fibered iodine stabilized laser system is under development to match several space missions requirement