OLED and OPD-based mini-spectrometer integrated on a single-mode planar waveguide chipM. Ramuz, D. Leuenberger, R. Pfeiffer, L. Bürgi and C. WinnewisserEur. Phys. J. Appl. Phys., 46 1 (2009) 12510DOI: https://doi.org/10.1051/epjap/2009025