CDL News

We are pleased to announce the launch of our new and improved section for NRAO's Central Development Laboratories. Now featuring expanded information and details about our operations. Please look around and explore!

The NRAO Central Development Laboratory (CDL) has developed and built several cryogenic low noise amplifiers for the 67-90 GHz frequency range near the practical noise limit using two different technologies: hybrid “chip-and-wire” and monolithic microwave integrated circuit (MMIC).  Read more.

The final acceptance of the ALMA correlator, developed and built at the CDL, occurred on December 20, 2012. The ALMA correlator's 134 million processors will continually combine and compare the signals from the 50 antennas in the main ALMA array plus up to 14 of the 16 antennas in the Atacama Compact Array (ACA), for a total of 64 antennas. At the correlator's maximum capacity of 64 antennas, there are 2,016 antenna pair combinations, and as many as 17 quadrillion calculations every second. The correlator is housed in the ALMA Array Operations Site (AOS) Technical Building, the highest-altitude high-tech building in the world.

Filters are used in virtually all electronic systems to define the operating frequency range and prevent unwanted, out-of-band energy from propagating to downstream components. This is important to improve dynamic range, suppress spurious signals and image bands, and limit interactions between high- and low-frequency components. In conventional filter structures, however, this is accomplished by reflecting the stop-band portion of the spectrum back to the source, which can sometimes cause problems of its own, usually through interaction with frequency-converting elements like multipliers or mixers. These issues are increasingly important as technology trends toward broader-bandwidth components and more tightly-integrated systems.

A recent patent issued to Matt Morgan, CDL Research Engineer, concerns a novel circuit structure comprising a "Reflectionless Filter," wherein the stop-band energy is absorbed internally rather than being reflected back to the source. In microwave terminology, the input impedance is theoretically constant at all frequencies (pass-band, stop-band, and transition-band).

This prevents the build-up of out-of-band standing-waves and eliminates interactions between components operating at different frequencies. It also makes them cascadable, so that small filtering elements may be placed at multiple points throughout the signal path to optimize sensitivity and dynamic range.

These filters, which can be low-pass, high-pass, band-pass, band-stop, and even multi-band, are very easy to implement and have a number of advantages besides the reflectionless property for which they were developed. Despite exhibiting a third-order, inverse-Chebyshev response, all elements of a single type -- resistor, inductor, or capacitor -- have the same value, no matter what the order of the filter. Not only does this simplify design, fabrication, and tuning, it limits the required elements to more nominal values which extend the applicable frequency range for a given technology. The filter response is also more stable with respect to component variation (say, with temperature) than conventional filters. Finally, despite containing resistive elements, the insertion loss of these filters in the pass-band is nominally zero, and is degraded less by low-Q components than their conventional filter counterparts.

The goals of the Nancy Grace Roman Technology Fellowship in Astrophysics program (see https://science.nasa.gov/researchers/sara/fellowship-programs/nancy-grace-roman-technology-fellowships-astrophysics-early-career-researchers) are to give early career researchers the opportunity to develop the skills necessary to lead astrophysics flight instrumentation development projects and become principal investigators (PIs) of future astrophysics missions; to develop innovative technologies that have the potential to enable major scientific breakthroughs; and to foster new talent by putting early-career instrument builders on a trajectory towards long-term positions.

Dr. Noroozian's fellowship was awarded together with a major research grant from NASA to develop three enabling technologies for next-generation Mid-Far Infrared cryogenic telescopes. One is a game-changing detector technology called “Photon-Counting Kinetic Inductance Detectors” - a mission-enabling tool for NASA's Origins Space Telescope (OST). Building these detectors is one of the most difficult technology challenges for the OST and may determine whether the observatory can be built. These detectors will see the faintest signals down to single photons -a holy grail in astrophysics - and can be used to map the composition and evolution of water and other key volatiles in planet-forming materials around young stars. The second technology is a miniaturized on-chip multi-object spectrometer that will be attached to the detectors to provide information about the spectral content of light detected from highly redshifted galaxies, and will aid in understanding of the evolution of galaxies and growth of structure in the universe. The third technology is quantum-noise-limited parametric amplifiers, which can amplify electromagnetic signals at the highest fidelity allowed by the uncertainty principle. Realization of the above technologies will enable a wide spectrum of science investigations for future space telescopes. Dr. Noroozian was also recently funded by the NRAO to develop parametric amplifiers to increase the sensitivity and observing speed of the ALMA telescope.

Dr. Ir. Omid Noroozian, an associate scientist and senior research engineer with the National Radio Astronomy Observatory’s Central Development Laboratory, was honored with NASA’s prestigious Nancy Roman Grace Technology Fellowship in Astrophysics.

This fellowship program, awarded by NASA headquarters, began in 2001 and gives early career researchers the opportunity to develop the skills necessary to lead astrophysics flight instrumentation development projects and become principal investigators (PIs) of future astrophysics missions; to develop innovative technologies that have the potential to enable major scientific breakthroughs; and to foster new talent by putting early career instrument builders on a trajectory toward long-term positions.

“I am greatly honored to receive this recognition,” said Noroozian. “The intersection between engineering, applied physics, and basic science is critical to advancing our understanding of the universe. My work, along with the combined efforts of my colleagues at NRAO, University of Virginia, NASA’s Goddard Space Flight Center, Johns Hopkins University, and SRON (Netherlands) can hopefully lead to major technological breakthroughs and new insights in astrophysics.”

Noroozian’s fellowship was awarded, together with a major ROSES-APRA research grant from NASA, to develop three enabling technologies for next-generation Mid-Far Infrared cryogenic space telescopes.

The first of these is a game-changing detector technology called “Photon-Counting Kinetic Inductance Detectors” — a mission-enabling tool for NASA’s envisioned Origins Space Telescope (OST). According to the citation, building these detectors is the single most difficult technology challenge for the OST and may determine whether the observatory can be built. These detectors will see the faintest signals, down to single photons — a holy grail in astrophysics research, and can be used to map the composition and evolution of water and other key molecules in planet-forming materials around young stars, and will see the thermal emission from rocky planets in the habitable zone of stars.

The second technology is a miniaturized on-chip, multi-object spectrometer that will be attached to the detectors to provide information about the spectral content of light detected from extremely distant galaxies. This will aid in understanding the evolution of galaxies and the growth of structure in the universe.

The third technology is quantum-noise-limited parametric amplifiers that can amplify electromagnetic signals at the highest fidelity allowed by the laws of quantum mechanics, which govern the rules of nature at the very smallest of scales.

Bringing these technologies to fruition will enable a wide spectrum of science investigations for future space telescopes. Noroozian was also recently funded by the NRAO to develop parametric amplifiers to increase the sensitivity and observing speed of the ALMA telescope.

The Roman Technology Fellowship in Astrophysics program is named after Dr. Nancy Grace Roman.  Dr. Roman is a distinguished American astronomer whose career has ranged from scientific research, to creating the first NASA astronomical program, to working with the teachers and students of today. Dr. Roman was instrumental in establishing the new era of space-based astronomical instrumentation. She is known to many as the “Mother of Hubble” for her role in planning the Hubble Space Telescope. For more information see:  https://science.nasa.gov/researchers/sara/fellowship-programs/nancy-grace-roman-technology-fellowships-astrophysics-early-career-researchers