New approach to image amplification based on an optically-pumped multi-core optical fiber

This paper describes a new approach to amplify optical images by using optically pumped doped cores in a multi-core optical fiber structure. This approach combines the high gain and high efficiency properties of cladding pumped optical amplifiers with the imaging properties of coherent fiber bundles. The individual cores correspond to the pixels in the image amplifier. We have demonstrated 3x3 arrays in an ytterbium-doped phosphate fiber energized by one multimode semiconductor diode. Each pixel is capable of high gain (> 20 dB), low noise, and large acceptance angle (>12 degrees). We expect our glass and preform fabrication method to scale to over 100 pixels. The amplified image can preserve coherence (phase and wavelength) or scramble the coherence depending on the design of the cores. This image amplifier is an enabling technology for any type of imaging system that is photon-starved and requires a compact and low noise image amplifier.