1. 1 Jet Propulsion Laboratory California Institute of Technology High Photon Efficiency Physical Layer – Initial Recommendations July 15, 2015 The research described in this publication was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

2. 2 Jet Propulsion Laboratory California Institute of Technology Status of High Photon Efficiency Specification Coding & Modulation White Book – First draft released December 2014 – Current draft released March 2015 – Next steps Revise to use common terminology Receive comments from agencies Physical Layer White Book – Initial draft released July 2015 – This presentation: summary of physical layer specification – Next steps Receive comments from agencies

3. 3 Jet Propulsion Laboratory California Institute of Technology Physical Layer – Downlink Center wavelength: 1550 nm – Leverages COTS investment in 1550 components, fiber Laser tuning range: 1 nm – TBD, based on 0.1 nm/ ⁰C and 10⁰C operating range Laser line width: < ±0.05 nm Laser relative intensity noise, frequency noise, phase noise: N/A – Not important for intensity modulations In band emission: 95% energy in < 0.1 nm (TBC) Polarization: linear – It is circularized to RHCP or LHCP as defined by IEEE prior to exiting the terminal aperture Polarization extinction ratio: > 20 dB Extinction ratio: > 33 dB Timing jitter: < 1/10 of minimum slot width

4. 4 Jet Propulsion Laboratory California Institute of Technology Physical Layer – Uplink Center wavelength: 1060 – 1080 nm – Chosen for availability of high power lasers (kWs at 1070) Laser tuning range: 1 nm Laser line width: < 0.2 nm Extinction ratio: > 13 dB Polarization: no