ABSTRACT

Wavelength division multiplexing (WDM) is a technology to increase the transmission capacity in an optical fiber, where multiple wavelengths carry data simultaneously. In addition to the effect of increasing the transmission capacity, WDM is also useful for wavelength-based switching, which enables us to set an optical path, which is routed on several fibers by connecting each wavelength per fiber through optical crossconnect(s). A network that is formed by several optical paths is called an optical path network, where each wavelength is related to a different optical path destination. Different paths accommodated in each fiber must use different wavelengths. This raises the problem of how to assign wavelengths to the paths while minimizing the number of wavelengths required. The problem is called a wavelength assignment problem. This chapter introduces wavelength assignment problems in an optical wavelength-routed network.