Optimisation of a fibre-based two-colour balanced optical cross-correlator

As part of the ongoing Full Energy Beam Exploitation (FEBE) upgrade to the Compact Linear Accelerator for Research and Applications (CLARA) at the Daresbury Laboratory, UK, few-femtosecond optical synchronisation between the new Ti:Sapphire terawatt FEBE laser and the Er:Yb optical master oscillator (OMO) is required for user experiments. To achieve this, a fibre-based two-colour balanced optical cross-correlator (BOXC) using waveguided periodically-poled lithium niobate (PPLN) crystals is being developed. A fibre-based BOXC could have greater sensitivity to timing jitter between two lasers than traditional free-space devices. In this manuscript, the design of the fibre-based two-colour BOXC is presented. The effect of pulse chirp on the sensitivity of the BOXC is investigated, and plans for optimising the design of the BOXC are discussed along with plans for integrating the fibre-based BOXC into the optical synchronisation network at Daresbury.