Laser direct writing of photonic structures in X-cut lithium niobate using femtosecond pulses

We have fabricated straight line structures and Y-couplers in X-cut lithium niobate crystals using femtosecond laser pulses. A systematic characterization study was performed initially to determine the effects of pulse energy on feature size. The optimal parameters were determined from experiments and simulations obtained using a two dimensional split step beam propagation method. Later the waveguides and couplers were fabricated using these optimized parameters. We present our results on the physical and optical characterization of these structures.