We report about optical spectrometry using gold nanostructures printed on top of an integrated optical waveguide. The optical waveguide is a single-mode buried waveguide made from a combination of photo-polymerizable materials and is fabricated by photolithography on a glass substrate. To detect the electric field inside the waveguide, a gold nanocoupler array of thin lines (50 nm thick and 8 μm in length) is embedded on top of the aforementioned waveguide. They are produced by e-beam lithography. Both waveguide ports are polished, and the output port, in particular, is coated with a thin gold layer to assimilate a mirror and hence, it enables the creation of stationary waves inside the structure. Stationary waves generated inside the guide constitute a spatial interferogram. Locally, light is out-coupled using the nanocouplers and allows measuring the interferogram structure. The resulting pattern is imaged by a vision system involving an optical microscope with the objective lenses of different magnifications and a digital camera mounted on top of the microscope. The 5× objective lens demonstrates a superior performance in retrieving the investigated spectrum compared to 20× and 100× objectives. Fast Fourier transform is performed on the captured signal to extract the spectral content of the measured signal.