Abstract
Signal amplification at the polymer optical fiber low-loss window of 650 nm is reported in an SU8 rib waveguide coated with Rhodamine-640 doped poly(methyl methacrylate). A signal beam is end-fired into the facet of a
7
×
100
μ
m
waveguide and amplified by top pumping of the
2
-
μ
m
-thick cladding region with a pulsed pump source focused into a 9-mm-long stripe. A gain of 14dB and a minimum signal-to-noise ratio of around 2 dB are achieved in a 15-mm-long device with a low threshold pump intensity of
0.25
μ
J
∕
mm
2
, which is an order of magnitude lower than previously reported.