An Optical Filter for Underwater Laser Communications

Abstract: Optical filters for underwater laser communications have been under development for some time. A free space laser communications system operating in the blue-green portion of the electromagnetic spectrum has the potential to transmit at very high data rates between platforms underwater and to those above the water. Operation during the day requires the ability to receive the maximum amount of light from the laser source coming from a range of angles and simultaneously filtering out solar background noise. We have developed a wavelength-tunable, wide field-of-view, narrow passband, large aperture filter. The filter we have developed is based on a Lyot type birefringence interference filter