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Highly Reliable and High Power 980 nm Pump Laser Diode Module for Undersea Cable Systems
Masashi USAMI Yuichi MATSUSHIMA Hideyoshi HORIE Hideaki KANEDA
IEICE TRANSACTIONS on Communications
Publication Date: 2001/05/01
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Joint Special Issue on Recent Progress in Optoelectronics and Communications)
Category: Optical Active Devices and Modules
980-nm pump laser, EDFA, WDM, undersea system, reliability,
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Highly reliable and high power weakly index guided buried-stripe type 980 nm pump laser diodes developed for undersea applications are reviewed. The 10,000-hour large scale reliability tests of the first generation LD chips shows that 16.7 FIT for the random failure was confirmed at 10C with 60% confidence level at 120 mW output power. We also fabricated a FBG locked co-axial type module using a can-sealed LD with a two-lens system, which showed a stable FBG locked mode oscillation at 980 nm under the temperature range from 5C to 45C. The 5,000-hour heat cycle test of the modules reveals that the cumulative failure rate after 27 years at 10C is expected to be 0.023%. These first generation LD modules were employed in the transoceanic commercial systems such as Pacific Crossing-1 and the Japan-US cable system projects. We have also succeeded in developing the 980 nm LD for higher output operation with optimizing waveguide design. The 1000 µm long LD showed CW kink-free operation up to 545 mW optical output and a maximum output power of over 650 mW, which was limited by thermal rollover. In addition, a preliminary aging test at 350 mW optical output power at 50C has shown stable operation up to 2,300 h. We also confirmed 300 mW kink-free fiber output power with a co-axial type module with the improved coupling efficiency of approximately 78%. These figures are the highest reported operation levels for 980-nm co-axial type modules.