A small size, low power consumption optical signal processing apparatus is implemented. An optical packet is split into two portions, one of which is used for an optical pulse generator to generate a single optical pulse or an optical pulse train with a period k times the bit period of the optical packet. The single pulse or the optical pulse train is used for an all-optical serial-to-parallel converter utilizing a surface-normal optical switch to convert a second portion of the optical packet into k parallel optical signals, which are then converted into k parallel electrical signals by a photo detector array. The k parallel electrical signals are supplied to an Si-based electronic circuit that implements high-speed optical signal processing. By utilizing the electronic circuit as a memory circuit or label recognition circuit, a buffer processing, address extraction and the like can be implemented.