Xinhua News Agency, Tokyo, April 2 (reported by Zhang Zheng) -- Japan's Oki Electric Industry Co., Ltd. announced on the 2nd that the company successfully transmitted an optical signal with a transmission speed of 160 gigabits per second over a distance of 380 kilometers. This achievement will make it possible to transmit high-speed optical signals over longer distances. According to a press release issued by Oki Electric Industry, due to the effects of waveform distortion and signal jitter during the transmission process, the higher the transmission rate, the shorter the transmission distance.