We demonstrate what is to our knowledge the first all-fiber squeezing exper
iment. A balanced Sagnac loop is used, and a record 6.1 +/- 0.2 dB of noise
reduction below shot noise has been obtained without stabilization. A giga
hertz Er-doped fiber laser and a high-power double-clad Er-Yb amplifier hav
e been developed to suppress guided acoustic-wave Brillouin scattering and
to make possible the all-fiber configuration. (C) 2001 Optical Society of A
merica.