Interoperability Testing for Lasercom Systems

Over the last decade, approximately a dozen different lasercom standards have emerged to facilitate interoperability between terminals from different vendors. To provide a capability for assessing standards compliance of terminals built by industry, MIT Lincoln Laboratory has built an Optical Terminal Verification Testbed (OTVT). The testbed provides emulation of both the channel and a remote terminal, and is used to assess both functional interoperability and quantitative performance. Emulated aspects include far-field propagation, line-of-sight jitter, the fading channel, pointing, acquisition and tracking (PAT), point-ahead angle, and Doppler shift. Full-duplex communication is supported in both fiber-to-fiber and free-space configurations at a variety of data rates and waveform formats. In addition, the OTVT facility provides a high-performance telemetry system to record terminal behavior and generate data products (e.g., tables, analytics, and visualizations). Here we describe the role of standards in assuring interoperability among terminals from different vendors, and the role of independent testbeds in evaluating standards compliance. We will also describe the capabilities of the OTVT facility, including free-space optical channel emulation, terminal emulation, and the suite of tests that can be performed.