Radiation Tolerant Fiber Optic Communication

Utilizing fiber optic technologies on strategic defense programs such as Navy Boost Vehicles is desirable for the high communication speeds, weight savings, relative size, reduced power draw and inherent EMI protection. However, it is not fully understood if the current COTS fiber optic technology can operate reliably in the complex and hostile radiation and space plasma environments missile sub-systems may be exposed to. These hostile environments include high dose rates up to 1E13 rad(Si)/s, total ionizing dose (TID) up to 5E5 rad(Si), Neutron Displacement Damage up to 1E14 neutrons/cm2, X-ray fluences up to 10 cal/cm2, and natural space conditions exposing platforms to high densities of high energy plasma species and large thermal changes. While the transmission in the fiber optic cable itself is inherently protected from electromagnetic interference (EMI) and EMP affects compared to traditional copper comms, the fiber is still susceptible to degradation from X-rays, gamma rays, protons, electrons, heavy ions, and neutrons. This degradation can take the form of darkening the fiber optic materials, greatly hindering, or completely ceasing optical transmission through the fiber. Currently there are several suppliers of “rad-hard” fiber optic cabling and transceivers on the market, but in the Phase I Base effort EMA conducted a SWaP (size, weight, and power) analysis and recommended two different cabling and transceiver options to be the focus for testing and simulation in the Phase II effort because of their radiation tolerance, high performance, maintainability, and SWaP advantages over traditional copper cabling. The Prysmian group DrakaElite “Super RadHard” Specialty Fibre, Weinert Mil-Spec Radiation Hard J-Fiber cabling, Samtec Firehawk Transceiver, and the Smiths Interconnect SpaceABLE 10G SL transceiver. In the Phase I Option EMA will work with NSWC Crane and Radiation Test Solutions to create test plans for evaluating the performance of the radiation tolerant fiber optic systems when exposed to neutron irradiation, TID, and high dose rate, and X-ray. The tests will be conducted in the beginning of Phase II effort with a focus on evaluating performance during irradiation. Simulations of these tests will then be created and validated in the EMA3D software package. After the simulation models have been validated with high confidence, the radiation sources and ambient environment will be modified to predict the performance of the fiber optics systems in environments not possible or feasible to test in a laboratory environment. This is the unique value proposition that EMA can bring to the fiber optic assessment, as we are of the very few who can marry simulation and measurement of radiation effects in such a way as to extract higher fidelity in our analysis then you could with only simulation or only measurement.