EurOCEAN 2000 - Vlaams Instituut voor de Zee

two spectral ranges by exploiting the first and second order of diffraction. Thus, the 800 nm -
940 nm range is available for SERS and salinity optodes with an average resolution of 3.4 cm -1
per pixel and at the same time the 420 nm - 680 nm range for luminescence and absorption
spectroscopy with a pixel resolution of 4.6 cm -1 . The 50 fibers of 50 µm core diameter at the
entrance slit are currently split up into 4 different bundles suitable for four measuring channels.
In addition to the spectrometer, the CI contains small and robust diode lasers with drivers and
temperature controllers, electronics for the CCD control and data communication. All parts of
the core instrument are integrated into a cylindrical housing of 1 m length and 250 mm outer
diameter. The prototype CI having passed the pressure test is shown in Fig.2.
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Fig.2 VIS/NIR core instrument after pressure testing
The FT-IR instrument contains a commercially available FT spectrometer whose optical and
electrical components had to be completely rearranged to fit into the housing. The design is
shown in Fig. 3. The fabrication of the instrument is currently being finished. The fibre-optic
sensor is directly attached to the front plate to use a short fibre length.
Fig.3 Underwater FT-IR instrument
Tests under Simulated Field Conditions
The construction of prototype equipment is accompanied by a series of tests which included as
a first step the basic laboratory characterization of the sensors. A second test phase was