A compact transverse-electric (TE)-pass polarizer for slot waveguides based on an asymmetrical directional coupler is proposed, where a slot waveguide and a linearly tapered waveguide (TW) cascading a hybrid plasmonic waveguide (HPW) are utilized. By properly choosing the structural parameters, the TW is cutoff for TE mode and the phase-matching condition is only satisfied for transverse-magnetic (TM) mode. As a result, the injected TM-mode can be evanescently coupled to the adjacent TW and then attenuated via the HPW while the input TE-mode will directly output, realizing an efficient TE-pass polarizer. With the help of the tapered structures, extinction ratio (ER) is enhanced and fabrication requirements are relaxed. Results show that the proposed polarizer has an ER of 27.1 dB at $1.55~\mu \text{m}$ , and its bandwidth is ~170 nm for an ER > 20 dB and an IL < 0.6 dB. In addition, fabrication tolerances to the key dimensions are analyzed and field evolution is also presented.