Specialty Optical Fibers Handbook

Chapter 7

Rare Earth-Doped Fibers

David J. DiGiovanni,

1

Roman Shubochkin,

2

T. F. Morse,

2

and Borut Lenardic

3

1

OFS Bell Labs, Murray Hill, NJ

2

Laboratory for Lighthouse Technology, Boston University, Boston, MA

3

Optacore d.o.o., Ljubljana, Slovenia

7.1 INTRODUCTION

Rare earth (RE) doping of optical fibers dates back to the 1960s and was one of

the forces driving development of guided wave optical fibers. The goal was to

exploit the long path length provided by wave-guiding media to improve operation

of Nd, Er, and Er/Yb fiber lasers. Then, as now, the fiber consisted of regions with

raised refractive index to guide light and some distribution of RE ions