We propose a compact polarization-independent output grating coupler, which consists of T-shaped grooves. For only 20 periods on a silicon-on-insulator wafer with a $260\mathrm{nm}$ thick top silicon layer, the output coupling efficiencies for both the TE and the TM modes are larger than 50% in the wavelength range of 1480– $1580\mathrm{nm}$ and are approximately 58% around $1550\mathrm{nm}$ . The polarization-dependent loss of the device is within $0.05\mathrm{dB}$ in the range of $1510–1580\mathrm{nm}$ .