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A new surface-plasmon-resonance (SPR) waveguide biosensor with the capability of bipolarization wavelength interrogation is presented. In the conventional SPR biosensors, only the transverse magnetic (TM)-polarized lightwave can couple with the surface plasma wave. The proposed SPR biosensor can make both the TM- and the transverse electric (TE)-polarized lightwave to produce the SPR. Therefore, two kinds of biomaterials can be separately detected by the signals from the TM- and the TE-polarized modes, and the number of detectable materials in a single chip can be doubled. Human serum albumin is coated on the device to sense the concentration of beta-blocker. Experimental results show that the concentration of beta-blocker is related to the SPR wavelength shift at a rate of 0.08 and 0.027 nm/ppm for the TM- and the TE-polarized modes, respectively.