fig2 shows a multichannel wavelength measurement device 200 multiple optical detectors are provided to detect light at different wavelengths in this example detectors 202 204 206 and 208 shown these detectors can be of conventional design used to detect light at certain wavelengths for the purposes of this patent application the term u201c light u201d includes both visible light and other forms of optical energy such as infrared light a sequence of optical splitters 208 210 and 212 are placed in the optical path 214 the optical splitters are adapted to preferentially provide enough light to one of the detectors at the desired detected wavelength of the detector for example in fig2 the optical splitter 208 preferentially reflects light at wavelength d 1 to the optical detector in one embodiment the optical splitter 208 preferably transmits light at the wavelengths d 2 d 3 and d 4 to detectors 208 204 and 206 also shown in fig2 is an optical mirror 216 the optics 218 220 222 and 224 can be used to focus the light to the detectors 202 204 206 and 208 looking again at fig2 note that this embodiment does not show filters associated with the detectors 202 204 206 and 208 however additional optical band pass filters may be used to further filter the light energy going to the detectors the efficiency of the optical energy detected is improved over the prior art systems by preferentially providing light using the optical splitters rather than using a traditional optical splitter more of the optical energy at the wavelengths of interest are sent to the detectors preferentially providing light means reflecting or transmitting light at a desired wavelength more.