Optical fibre and optical fibre amplifier for light amplification

Abstract

An optical fiber (1) for optical amplification used for 1.58 um band signal light amplification, at least a core region(11)thereof being doped with Er, is characterized in that at least a part of the core region(11)is made of silica glass co-doped with Ge and Al together with Er, an average Er atomic concentration in the core region(11)is from 950 wt-ppm to 3000 wt-ppm inclusive, and a mode field diameter in the 1.58 um band is more than 5 um.

Description

technical field [0001] The present invention relates to an optical fiber amplifier that injects excitation light and signal light, amplifies the signal light and outputs the signal light, and an optical amplifying optical fiber used in the optical fiber amplifier, particularly an optical amplifying optical fiber in which erbium is added to at least a part of the core, and the use of the optical fiber fiber amplifier. Background technique [0002] In an optical fiber communication network, wavelength division multiplexing (WDM: Wavelength Division Multiplexing) communication technology is known as a method of increasing the amount of information that can be transmitted, that is, the communication capacity. [0003] In this WDM communication, development of an ultra-wideband optical fiber amplifier capable of collectively amplifying WDM signal light is required. An example of this technique is disclosed in Makoto Yamada et al., "Ultra-Wideband Optical Fiber Technology Capable...

AI Technical Summary

Problems solved by technology

[0004] However, the magnification per unit length of the 1.58 μm band of the Er-added fiber used in fiber amplifiers so far is smaller than that of the 1.55 μm band per unit length (gain per unit length) by more than one order of magnitude, so in order to obtain the same With the same signal gain, the length of the optical fiber for amplification needs to be more than 10 times, and the length will be hundreds of meters long, which will increase the size of the device

[0005] In order to increase the gain per unit length of the optical fiber for amplification, it is conceivable to increase the amount of Er addition to increase the amount of excitation light absorption caused by Er. However, when the concentration of Er increases, the conversion efficiency will decrease due to concentration extinction.

For example, the inventors of the present invention reported an EDF that increased the Er concentration to 1100 wtppm in "Research on EDF with High Unit Length Gain in the 1580nm Band" (Journal of the Electronics and Communications Society of Japan OAA'98C-3-3), but, This is an Er addition concentration that is substantially close to the hitherto considered concentration extinction limit

Images