| 摘要 |
PURPOSE:To make improvement in the gain of the optical fiber amplifier by specifying the mode field diameter of a rare earth-doped fiber to about 6.5mum when dispersion shift fibers of about 8mum mode field system are used on the input and output sides of the rare earth-doped fiber. CONSTITUTION:The mode field diameter of the erbium-doped fiber 1 is specified to 6.5mum when the mode field diameter of the ordinary optical fibers 4 to 6 provided on the input and output sides of the erbium-doped fiber 1 is specified to 8mum. Namely, the optimum mode field diameter of the erbium-doped fiber 1 is determined by taking both of the gain by the mode field diameter of the erbium-doped fiber 1 and the connection loss by the connection between the ordinary optical fibers 4 to 6 used for the input and output into consideration. The gain of the optical fiber amplifier 10 is increased most in this way. |
