Coherent integration of 0.5 GHz spectral holograms at 1536 nm using dynamic biphase codes

Spectral hole-burning-based optical processing devices are proposed for coherent integration of multiple high-bandwidth interference patterns in a spectral hole-burning medium. In this implementation, 0.5 GHz spectral holographic gratings are dynamically accumulated in ${\mathrm{Er}}^{\text{3+}}:{\mathrm{Y}}_2{\mathrm{SiO}}_5$ at 4.2 K using a 1536 nm laser frequency stabilized to a spectral hole, along with commercial off-the-shelf components. The processed data, representing time delays over 0.5–2.0 μs, were optically read out using a frequency-swept probe; this approach makes possible the use of low-bandwidth, large-dynamic-range detectors and digitizers and enables competitive processing for applications such as radar, lidar, and radio astronomy. Coherent integration dynamics and material advances are reported.