A method of designing a continuous-wave laser source having a target output wavelength and an input laser with a wavelength different from the target output wavelength includes the steps of receiving the target output wavelength, and subordinate properties of the laser source; determining a candidate wavelength of the input laser and materials of the substrate, lower cladding, photonic device layer (PDL), and upper cladding; producing an optimal design of a photonic crystal resonator (PhCR) enabling optical parametric oscillation (OPO); and producing an optimal design of the input and output PhCR waveguide couplers. The OPO is phase-matched.