Conversion of 8000 m class Optical - Electric composite armored cable

JAMSTEC has a stock drum winch which was winded 8000 m class Optical - Electric composite armored cable (composite cable) for using Deep-Tow. In fiscal 2011, by using the composite cable, JAMSTEC conducted research cruise for 2011 Tohoku earthquake. But, an optical trouble was happened, and communication by using the composite cable became impossible between Deep-Tow and mother ship. On the other hand, this composite cable is necessary for great depth sea survey for example source zone survey of 2011 Tohoku earthquake. So conversion of composite cable is immediately required. Therefore the composite cable's renewal was done. Through the renewal, the optical loss budget was drawn for composite cable to be operated over 5000 m depths. It is confirmed that the optical loss of the underwater optical connector is within the range of the optical loss budget. The utilizable channel of this cable is improved from two channels to four channels. And the optical loss was also measured in operation during free-fall. In this paper, the author report above.