In this work, a new nanohybrid saturable absorber (SA) is successfully fabricated from reduced graphene oxide (rGO) nanosheets and titanium dioxide (TiO₂) nanoparticles. The nanohybrid material is synthesized using the simple and inexpensive hydrothermal technique. The SA is fabricated by depositing the nanohybrid solution onto a D-shaped fiber in an erbium-doped fiber (EDF) laser cavity. The evanescent wave interaction between the incident light and rGO-TiO₂ nanohybrid material induces mode-locking in the EDF laser at the threshold pump power of 100.80 mW. A stable soliton pulse with a center wavelength of 1560.45 nm and 3-dB bandwidth of 2.47 nm is obtained. The generated pulses have a repetition rate and pulse width of 11.19 MHz and 1.05 ps at the highest pump power of 268.10 mW. The proposed rGO-TiO₂ nanohybrid of this work is a promising SA material for generating mode-locking in an EDF laser for optical modulation applications.