• Advanced volume holographic filter to improve the SNR of polychromatic sources in a noisy environment

      Alcaraz, P.E.; Blanche, P.-A.; Wyant College of Optical Sciences, University of Arizona (OSA - The Optical Society, 2021)
      We present a new type of filter that improves the SNR of systems where polychromatic signal and noise are located at different distances within the same line of sight. The filter is based on holographic technology that allows for the discrimination of wavefronts by range. In using a combination of two holographic elements, a pre-disperser and a thick volume hologram, we were able to significantly increase the spectral bandwidth of the filter, from 9nm without the pre-disperser to 70nm with both holographic elements. Laboratory proof of concept demonstrated that such a filter is capable of an SNR improvement of 15 dB for a monochromatic source, and up to 7.6 dB for a polychromatic source. This filter can find applications in astronomic observation, satellite or space debris tracking, and free-space optical communication. © 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
    • Cryogenic C-band wavelength division multiplexing system using an AIM Photonics Foundry process design kit

      Fard, E.M.; Long, C.M.; Lentine, A.L.; Norwood, R.A.; College of Optical Sciences, University of Arizona (OSA - The Optical Society, 2020)
      Cryogenic environments make superconducting computing possible by reducing thermal noise, electrical resistance and heat dissipation. Heat generated by the electronics and thermal conductivity of electrical transmission lines to the outside world constitute two main sources of thermal load in such systems. As a result, higher data rates require additional transmission lines which come at an increasingly higher cooling power cost. Hybrid or monolithic integration of silicon photonics with the electronics can be the key to higher data rates and lower power costs in these systems. We present a 4-channel wavelength division multiplexing photonic integrated circuit (PIC) built from modulators in the AIM Photonics process development kit (PDK) that operate at 25 Gbps at room temperature and 10 Gbps at 40 K. We further demonstrate 2-channel operation for 20 Gbps aggregate data rate at 40 K using two different modulators/wavelengths, with the potential for higher aggregate bit rates by utilizing additional channels. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
    • Quantum-limited discrimination of laser light and thermal light

      Habif, J.L.; Jagannathan, A.; Gartenstein, S.; Amory, P.; Guha, S.; College of Optical Sciences, University of Arizona (OSA - The Optical Society, 2021)
      Understanding the fundamental sensitivity limit of an optical sensor requires a full quantum mechanical description of the sensing task. In this work, we calculate the fundamental (quantum) limit for discriminating between pure laser light and thermal noise in a photon-starved regime. The Helstrom bound for discrimination error probability for single mode measurement is computed along with error probability bounds for direct detection, coherent homodyne detection and the Kennedy receiver. A generalized Kennedy (GK) receiver is shown to closely approach the Helstrom limit. We present an experimental demonstration of this sensing task and demonstrate a 15.4 dB improvement in discrimination sensitivity over direct detection using a GK receiver and an improvement of 19.4% in error probability over coherent detection. © 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
    • Random quasi-phase-matching in polycrystalline media and its effects on pulse coherence properties

      Gu, J.; Schweinsberg, A.; Vanderhoef, L.; Tripepi, M.; Valenzuela, A.; Wolfe, C.; Ensley, T.R.; Chowdhury, E.; Kolesik, M.; James Wyant College of Optical Sciences, University of Arizona (OSA - The Optical Society, 2021)
      Polycrystalline materials can mediate efficient frequency up-conversion for mid-infrared light. Motivated by the need to understand the properties of the harmonic and supercontinuum radiation from such media, we utilize realistic numerical simulations to reveal its complex temporal and spatial structure. We show that the generated radiation propagates in the form of long-duration pulse trains that can be difficult to compress and that optical filamentation in high-energy pulses gives rise to fine-structured beam profiles. We identify trends concerning pulse energy, sample length, and the microstructure of the material that can inform optimization for different applications. © 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement