TOKYO, Mar. 16 -- Mitsubishi Electric Corp. reported that it has developed a 980-nm pump laser diode with output power of 250-mW at 70 °C for an erbium-doped fiber amplifier employed in long-distance optical communication.According to Mitsubishi, the 980-nm pump laser diode reduces the noise figure by about 1 dB in comparison with that of the 1.48-µm pump laser diode commonly employed with optical fiber amplifiers. To achieve the necessary reliability, Mitsubishi produced a window structure at the diode surface, which broadens the bandgap, reducing light absorption and associated optical damage.