Boston Chapter of the IEEE Photonics Society

Abstract:  Falling launch costs are leading to a proliferation of small satellites in low Earth Orbit (LEO) that can overfly every point of the surface of the Earth and collect voluminous sensor data.  The timely return of this data to the surface of the Earth is a challenging technical problem.  Optical communication technologies provide a means for transferring this data without overwhelming the size, weight, and power accommodation of small satellites.  Recently, on orbit optical communication systems have adopted the traditional approach to solving this problem, relaying via satellites in geosynchronous orbit, however that requires the LEO satellite to close a 40,000 km communication link and suffers from significant latency.  A new alternative architecture, relaying via crosslinks within a constellation of LEO satellites, has the potential to further reduce the footprint and power consumption of optical terminals by reducing the link distance to a few 1000 km.  Moreover, this architecture greatly reduces communication latency as the total link distance is reduced from 80,000 km to less than 15,000 km.

Biography:  Dr. Yarnall has been actively contributing to research in the photonics community for many years.  He has a BS degree in applied physics from Caltech and an MS and Ph. D. degrees in electrical engineering from Boston University.  He has broad interests that include quantum optics, atmospheric propagation of optical signals, and coherent optical communications, and has published work in these areas in conferences and peer-reviewed journals steadily over his career.

Dr. Yarnall has been a significant contributor to many photonics technologies throughout his career.  At the beginning of his tenure at MIT Lincoln Laboratory he designed and constructed the low-noise optical amplifier for the world’s first high-rate space-borne laser communication demonstration.  He developed airborne optical terminals to support the exfiltration of large data volumes to ground sites. Following that, Dr. Yarnall led a team of engineers developing a high-speed high-sensitivity coherent optical modem.  In 2013, he published a world-record result where a coherent optical receiver demonstrated error-free performance at 10 Gb/s requiring only 2.1 photon per bit.  He has also developed an optical communication technology for high-rate communication between submerged vehicles based on photon counting at visible wavelengths.

More recently, his focus has returned to space-borne laser communication systems.  Presently, he is co-leading the development of two lasercom systems for human space exploration, one for the International Space Station and the other for the Orion’s return to cis-Lunar space.  Additionally, he is involved in the design of satellite constellations that employ optical crosslinks to support new space missions.