Ibsen Photonics - OEM Spectrometer and Transmission Gratings, Ibsen Photonics is the leader in fused silica transmission gratings, e.g. Phase masks, telecom, PCG and spectrometer gratings. By combining unique optical design capabilities with superior grating technology, Ibsen supplies compact, OEM spectrometers for applications such as UV, VIS, NIR, Raman, OCT, and fiber sensing.