This paper recommends a systematic wavelength assignment scheme which deliberately enhance the quality of service by minimizing the average dispersion in optical network. In this approach assignment of the wavelength recommended that allocates the wavelength as per mathematical model based on the path length request. Results validate that path length-based scheme improves the system performance in comparison with the commonly used existing assignment technique which works on the principle of first fit wavelength assignment(FFWA) and former assignment methodology should be ideal choice when the number of connection requests extremely high
