This paper highlights our recent advances in photonic transport network technologies, focusing on the optical path technologies such as WP (Wavelength Path) and VWP (Virtual Wavelength Path) schemes. They enhance not only transmission capacity but also cross-connect node throughput cost-effectively by capitalizing on the wavelength routing technique. A suitable photonic transport network architecture is identified. Optical switch boards developed for a large-scale optical path cross-connect system are also demonstrated.