Abstract

The introduction of Er doped fibers for amplification in optical communication systems has led to the possibility of long-haul, high-speed soliton based communication. There is a need for a simple inexpensive efficient source of solitons at a wavelength compatible with the Er amplifiers and a repetition rate suitable for the new high speed communication systems. In the past these pulses have been provided by either color center lasers (which are bulky, expensive and inefficient) or modelocked laser diodes (which have little output power and have a limited lifetime). In this paper we present an all-fiber laser that produces solitons by passive modelocking a fiber ring with a nonlinear amplifying loop mirror (NALM) containing an Er-doped section of fiber. This laser produces transform limited pulses as short as 2 ps, at an average power of 1.3 mW and a wavelength of 1.535µm, by passive modelocking. The idea of modelocking a laser using a nonlinear fiber mirror has been proposed^[1] and demonstrated^[2] for a linear laser using either a bulk optic or a fiber reflector at the other end of an amplifying segment. In this paper we would like to present a ring laser which is modelocked by a NALM, so that no active modelocking is necessary in the laser.

© 1990 Optical Society of America