All optical wavelength converter (AOWC) play important functionalities to enhance the network reconfiguration, efficient wavelength routing and assignment, non-blocking capacity in future dynamic optical access networks. In optical access networks, bandwidth limitation and wavelength continuity constraints lead to inefficient utilization of wavelength resources. AOWCs are the premier option to cope with these network constraints. On the other hand, advanced modulation formats have been extensively analyzed and used to achieve the high spectral efficiency. Since advanced modulation formats are more sensitive to amplitude and phase noise, AOWC are more suitable to achieve minimum power penalty and maximum conversion efficiency. In this paper, AOWC based on four wave mixing (FWM) in highly nonlinear fiber (HNLF) for coherent 100 Gbps dual-polarized differential quadrature phase shift keying (DP-DQPSK) has been designed. The performance of AOWC is optimized at different probe input power, different pump power and wavelength to achieve the maximum conversion efficiency. After the multiwavelength conversion based on 0.7 km HNLF, the power penalty for converted 100 Gbps DP-DQPSK signals is less than 4.15 dB at BER of 10-9 and maximum conversion efficiency of −10.58 dB has been achieved.