Recent developments in tunable laser diodes now make it possible to do
injection seeding of a quantum-limited Raman amplifier. We present da
ta from an experiment in which a tunable laser diode in the visible wa
s injected into a Raman amplifier with a coupling efficiency of 65% +/
- 45%. This efficiency approaches the theoretical limit of 100% and is
much larger than the 0.1-0.2% coupling efficiency reported in the lit
erature for a comparable experiment when an infrared laser diode is us
ed.