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We have observed the mid-infrared absorption spectra of D$2$O$\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$ using a tunable lead-salt diode laser spectrometer with velocity-modulation technique. The D$2$O$\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$ ions were generated in a water-cooled discharge of a mixture of D$2$O and helium. Spectra were collected in the region between 1000 and 1150 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$. Totally 64 lines were assigned to the $\nu$$2$ fundamental band of D$2$O$\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$ ($X~2$$B$$1$). Precise molecular constants have been determined.