Summary form only given: Current edge routers for carrier network have the total throughput of about 3.2 Tb/s for the backplane signal transmission. The total throughput is predicted to reach up to 12.8 Tb/s in 2014 because the data traffic increases about two times per two years. Such growth requires the development of higher speed and lower power backplane signal transmissions. To accommodate this situation, we are developing a compact photonic I/O based on a four-channel 25-Gb/s/ch transceiver, which consists of a four-channel laser diode (LD) array, a four-channel photodiode (PD) array, and one chip signal conversion CMOS circuit collaborating with PETRA, the Photonics Electronics Technology Research Association supported by NEDO. The circuit consists of a LD driver array and a trans-impedance amplifier (TIA) array and also a SerDes (Serializer/Deserializer) with logical circuits for data format conversion. The goal and present achievement of the project including photonic devices, a CMOS-TIA, and an integrated receiver will be presented.