Optical gain at 1.54 mum in erbium-doped silicon-rich silicon oxide (SRSO) is demonstrated. Er-doped SRSO thin film was fabricated by electron-cyclotron resonance enhanced chemical vapor deposition of silicon suboxide with concurrent sputtering of erbium followed by a 5 min anneal at 1000 degreesC. Ridge-type single mode waveguides were fabricated by wet chemical etching. Optical gain of 4 dB/cm of an externally coupled signal at 1.54 mum is observed when the Er is excited via carriers generated in the Si nanoclusters by the 477 nm line of an Ar laser incident on the top of the waveguide at a pump power of 1.5 W cm(-2). (C) 2001 American Institute of Physics.