1. Radiation Effects in Active Optical Components Robert A. Reed, Ken LaBel, Janet Barth, Henning Leidecker, Allan Johnston, Paul Marshall and Cheryl Marshall 4/27

2. Radiation Effects and Analysis Group 4/27

3. Outline • Introduction to radiation effects in optical components • Radiation environment • optical components • Radiation induced transients in optical components • Radiation induced degradation mechanisms in optical components • Summary 4/27

4. Total Ionizing Dose Single Event Transient 2.5 14 12 2.0 10 6 8 CTR 1.5 5 I-lite (mA) 6 4 4 1.0 (V) 3 2 2 0 0.5 0 20 40 60 80 100 120 1 Dose (kRad(Si)) 0 0 0 100 200 300 400 500 600 12x1010 0 4x1010 8x1010 Displacement Damage (ns) Fluence (p/cm2) Radiation-Induced Effects in Optical Components 4/27

5. Radiation Environments • Heavy Ion LET Spectra • Total Ionizing Dose • Proton Spectra 4/27

6. Heavy Ion 4/27

7. Total Ionizing Dose 4/27

8. Proton Environment 4/27

9. Equivalent Proton Fluence for Displacement Damage 4/27

10. LED DETECTOR Active Optical Components • Optical coupling of two electrical circuits with an optical transmitter and an optical receiver. • LEDs, Phototransistors, photodiodes, etc... • Optocoupler is one type of optical components • CTR = Io/ If 4/27

11. Total Ionizing Dose Single Event Transient 2.5 14 12 2.0 10 6 8 CTR 1.5 5 I-lite (mA) 6 4 4 1.0 (V) 3 2 2 0 0.5 0 20 40 60 80 100 120 1 Dose (kRad(Si)) 0 0 0 100 200 300 400 500 600 12x1010 0 4x1010 8x1010 Displacement Damage (ns) Fluence (p/cm2) Radiation-Induced Effects in Optical Components 4/27

12. 6 5 Amplitude (V) 4 3 2 1 0 0 100 200 300 400 500 600 (ns) A sample SET from an HP QCPL-6731 Optocoupler Single event transients induced in photodetector can be passed to circuitry that follows the optocoupler if the amplification stage recognizes the SET as a valid signal 4/27

13. 1.2E-07 0 degrees 1.0E-07 85 degrees 87.5 degrees /device) 90 degrees 8.0E-08 92.5 degrees 2 95 degrees 6.0E-08 Cross-Section (cm 4.0E-08 2.0E-08 0.0E+00 30 80 130 180 230 280 Proton Energy (MeV) Ground Based Single Event Transient Measurements 4/27

14. Total Ionizing Dose Single Event Transient 2.5 14 12 2.0 10 6 8 CTR 1.5 5 I-lite (mA) 6 4 4 1.0 (V) 3 2 2 0 0.5 0 20 40 60 80 100 120 1 Dose (kRad(Si)) 0 0 0 100 200 300 400 500 600 12x1010 0 4x1010 8x1010 Displacement Damage (ns) Fluence (p/cm2) Radiation-Induced Effects in Optical Components 4/27

15. Total Ionizing Dose Degradation of Phototransistor 4/27

16. Total Ionizing Dose Degradation of LED 4/27

17. Total Ionizing Dose Single Event Transient 2.5 14 12 2.0 10 6 8 CTR 1.5 5 I-lite (mA) 6 4 4 1.0 (V) 3 2 2 0 0.5 0 20 40 60 80 100 120 1 Dose (kRad(Si)) 0 0 0 100 200 300 400 500 600 12x1010 0 4x1010 8x1010 Displacement Damage (ns) Fluence (p/cm2) Radiation-Induced Effects in Optical Components 4/27

18. Optocoupler Current Transfer Ratio Degradation with Proton Fluence 4/27

19. DC/DC Power Converter that Contains an Optocoupler 4/27

20. LED Data from the Early 80’s 4/27

21. Various Optocoupler Results 4/27

22. Observed Properties of a “good” optocouplers • RADIATION RESPONSE IS KNOWN • Single Event Transient • Observed in devices that operate at > 5MhZ • Circuit filtering is possible • Total Ionizing Dose • Shielding may help reduce TID (WARNING) • Displacement Damage • Not Amphoterically doped • LED wavelength <800nm • Maximize LED drive (WARNING) • Operation of phototransistor in saturation 4/27

23. SUMMARY • Evaluation of three radiation induced effects is important for optical components links • SET, TID and Displacement Damage • Unable to predict radiation response from manufacture information • Data is available on some optical components • Radiation testing at off site proton facility • Simultaneous evaluation of SET, TID and Displacement Damage • Some optical components perform very well in the space radiation environment 4/27