Danish Optical Society (DOPS) - Professional organisation of people, institutions, and companies working with optics in Denmark.
European Optical Society (EOS) - Contributes to the scientific progress in optics and promotes their applications on the European and international levels.
Infrared Data Association (IrDA) - Standards body for wireless point to point IR. 150 member firms. Offers component and system resources, links to IR specific pages and more.
Optical Society of America (OSA) - Serves optics and photonics professionals around the world with conferences, peer-reviewed publications, and other services.