Previous designs of integrated photonic devices mainly included intuitive trial and error approach or optimization methods using parameter search algorithms. The small parameter space and poor investigation of the underlying physics limited the device performances, functionalities, and structural dimensions. Therefore, in this study, we demonstrate efficient and compact design of next-generation integrated photonic devices by using recently emerged objective-first inverse design algorithm. In this method, the target performance parameters to be achieved are first defined and then dielectric distribution of nanophotonic structures is obtained in an iterative manner. The proposed inverse designs of wavelength demultiplexer, optical filter and power splitter exhibited great device performances such as high transmission efficiency and small dimension together with new functionality. To summarize, the proposed photonic designs with great device performances are promising candidates for next-generation on-chip photonic applications necessitating superior properties of miniaturized optical components. © 2018 IEEE.