Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In wavelength division multiplexing (WDM) networks, failures may imply severe loss of data due to the high transmission rates, leading to the need for employment of protective mechanisms. Transparency and switching in all-optical networks cause physical impairment, which can significantly degrade signal quality. If the signal quality along a path is below acceptable values, this path cannot be used for incoming requests in the establishment of lightpaths. Therefore, quality must be checked by the routing and wavelength assignment algorithm. The present article introduces two novel algorithms for shared path protection in WDM networks that take into consideration the Polarization Mode Dispersion, Amplifier Spontaneous Emission, and homowavelength cross-talk physical impairments during path selection. The efficiency of these algorithms is compared to that of their impairment-unaware counterparts.192212222Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Cisco University Research Program (URP) ProgramFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)