Quantum dots have proved to be of great interest in being useful for the application of the GaAs-based optical devices at the wavelength of 1.3 or 1.55 mum suitable for fiber-optic communication system. We demonstrate 1.52 mum light emission with a narrow linewidth of 22 meV at room temperature from self-assembled InAs quantum dots embedded in an In0.45Ga0.55As strain-reducing layer. By capping InAs quantum dots with an InGaAs strain-reducing layer instead of GaAs, the PL peak of InAs quantum dots shifts towards a longer wavelength. We can control the PL peak of InAs quantum dots by changing the indium composition of InGaAs strain-reducing layer. We confirm that InAs quantum dots will also be useful for applications with GaAs-based optical devices that are suitable for fiber-optic communication systems. (C) 2002 Elsevier Science B.V. All rights reserved.