With conventional poling techniques of pyroelectric crystals, the thickness of the periodically poled crystals is typically limited to 0.5&\#x2013;1&\#x00A0;mm. Such a small aperture of the crystal limits the amount of energy/power that this device may deliver. Here we discuss diffusion bonding as an alternative method to achieve a wider periodically poled crystal, with virtually unlimited width. It is shown that the amplified signal preserved a good beam profile despite a possible phase shift between the stitched crystals. This technique may be extended to larger aperture optical parametric amplifiers and allows for high energy output from periodically poled crystals.