A less-complex 2.8-mm beam diameter spectral domain optical coherence tomography system with an adaptive optics module presented. In this system a Shack-Hartmann wavefront sensor used for aberration sensing and the Deformable mirror used for aberration correction. We demonstrated the diffraction-limited resolution performance of this system on model retina. On the model, measured speckle size with present system is 2.2 times smaller than a 1.2-mm beam diameter OCT system. Further, on the model eye SNR gain of 6.7 dB was quantified with the present system over a 1.2-mm beam diameter OCT system. Relatively small size of 25 cm by 50 cm, less complexity, large field of view of the present system as compared to the conventional AO-OCT systems, would make it suitable for ophthalmic clinical applications.