title: Toward a 3:1 frequency divider based on parametric oscillation using AgGaS(2) and PPLN crystals.
abstract: Frequency divide-by-two (2:1) and divide-by-three (3:1) optical parametric oscillators (OPOs) are basic devices for the implementation of future accurate optical frequency division chains. We report our latest development toward a phase-locked 3:1 frequency division of a radiation at lambda(p) approximately 843 nm (355.9 THz), using doubly resonant oscillators (DROs) based on silver gallium sulfide (AgGaS(2 ) or AGS) and multigrating periodically poled lithium niobate (PPLN). Although stable single-mode pair operation is achievable without any active cavity length servo with the AGS-DRO, because of a strong passive thermal feedback servo, the PPLN-DRO requires an active intensity side-of-fringe locking servo to maintain long-term, single-mode pair operation. To overcome the limited idler output power (<1 mW) due to the weak mirror transmissivity at 2.53 mum, a CaF (2) Brewster-oriented plate was inserted in a longer-cavity PPLN-DRO as a variable output coupler. About 3 mW of idler wave is thus coupled outside the cavity, yielding 15 nW of doubled-idler. We obtained a 30 dB signal-to-noise ratio beatnote in a 100 kHz resolution bandwidth of a spectrum analyser. This beat signal will be used to phase-lock the divider.
authors.affiliation: Lab. Primaire du Temps et des Frequences, Bur. Nat. de Metrol., Paris.
authors.forename: A
authors.initials: A
authors.lastname: Douillet
authors.forename: J J
authors.initials: JJ
authors.lastname: Zondy
authors.forename: A
authors.initials: A
authors.lastname: Yelisseyev
authors.forename: S
authors.initials: S
authors.lastname: Lobanov
authors.forename: L
authors.initials: L
authors.lastname: Isaenko