Ultra-compact and -broadband integrated gold plasmonic half-wave and quarter-wave plates (HWP and QWP) based on the mode interference mechanism are proposed with applications in magneto-photonics, mode- and polarization-division multiplexing. The numerical simulations based on a finite element method reveals that the proposed HWP offers a maximum polarization conversion efficiency of 99.6\(\%\) at a wavelength of \(\lambda _0\) = 1.55 \(\mu\)m with a 1 dB bandwidth of 140 nm (\(\lambda _0\) = 1.47–1.61 \(\mu\)m), covering 82\(\%\) of the S to L telecommunication bands. In this wavelength range, HWP has an insertion loss below 2.3 dB and an extinction ratio between 9 and 24 dB, respectively. The presented QWP functions over the C telecommunication band (\(\lambda _0\) = 1.53–1.565 \(\mu\)m), where the transmission contrast between its transverse magnetic and electric modes is 0±0.04. Moreover, QWP offers a polarization rotation angle in the range of 45±5\(^\circ\) over the same wavelength range. Finally, this paper illustrates that the proposed waveplates have a robust tolerance to fabrication errors.