We demonstrated a single-walled carbon-nanotube-deposited planar lightwave circuit (PLC) waveguide for four-wave-mixing (FWM)-based wavelength conversion. FWM is generated from the interaction between the propagating light through the PLC waveguide and the deposited carbon nanotubes (CNTs) on the overcladding-removed core of the waveguide. The third-order nonlinearity of the CNTs is originated from the interband transitions of the pi electrons causing nonlinear polarization similar to other highly nonlinear organic optical materials. FWM-based tunable wavelength conversion of a 10 Gbit/s non-return-to-zero signal is achieved with a power penalty of 3 dB in the bit-error-rate measurements. To our knowledge, this is the first demonstration of a CNT-technology-based device for integrated photonic applications.