The local density of states and response to an incident plane wave of a finite sized photonic crystal (PC) with nonlinear material (NLM) is analyzed. The 2D PC is a periodic array of 7 rows x 6 columns of round dielectric rods and there is a band gap associated with this small array. Since this array is not infinitely periodic, there is the possibility of defect modes. Of particular interest is the excitation of surface wave defect modes at the truncated surface of the PC, which is collocated with the NLM material. We use Dyson's equation to compute the 2D Green function of the PC with linear material and then include the Kerr NLM in a self-consistent manner. The 2D PC has one row of rods that are semi-circular and this has the effect of moving the surface wave defect mode frequency into the band gap. Since the surface modes are resonant at the interface, the NLM should experience at least an order of magnitude increase in field intensity. This is a possible means of increasing the efficiency of the PC as a frequency conversion device.

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