A method to fabricate conjugated polymer waveguides with well defined edge facets is demonstrated. The utility of the approach is explored for application as end-fired ultrafast optical amplifiers based on poly(9,9'-dioctylfluorene-co-benzothiadiazole). An internal gain of 19 dB was achieved on a 760 microm long waveguide at 565 nm wavelength. This fabrication procedure may be applied to a wide range of conjugated polymers and organic light-emitting devices, providing an important step towards future applications of organic integrated photonics.