Analytical design of a high bandwidth optoelectronic signal link for use in an EMP (electromagnetic pulse) plus radiation environment

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5019817

Anthes, J P

Electronic systems which must operate in an electromagnetic pulse (EMP) environment are often enclosed in a conducting box, or Faraday enclosure. The conducting walls must have apertures to allow communications with systems outside the enclosure. EMP leakage is minimized when the aperture diameter is small and has finite thickness. In addition, the penetration of a Faraday enclosure by a conductor may result in a significant portion of EMP induced noise inside the enclosure. Optical signals, because of their short wavelength, can efficiently traverse apertures that are highly attenuating to EMP signals. A communication link consisting of a GaAlAs laser diode source, optical fiber, and a photodiode detector is well suited to this application. Optical transport efficiency between an optical-fiber-coupled 10-stripe laser diode array and a radiation tolerant AlGaAs photodiode is optimized with a graded refractive index (GRIN) rod lens. The lens is positioned in the conducting wall of a Faraday enclosure. The radiation tolerant photodiode is contained inside the enclosure to control EMP induced degradation of the signal-to-noise ratio of the link. The AlGaAs photodiode double heterostructure design controls the ionizing-radiation-induced degradation of the link. An optical design analysis is performed to satisfy two criteria. First we select acceptable lens length-to-radius ratios for an aperture filled by a dielectric medium (the glass GRIN-rod lens). This criteria determines the upper limit on potential EMP leakage through the lens and into the Faraday enclosure. Second, we utilize the lens image condition to achieve 98% optical transfer between a nanosecond response, optical-fiber-coupled laser diode and the radiation hardened photodiode. 15 refs., 6 figs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5019817
• Report Number(s): SAND-87-3080C; CONF-880579-5; ON: DE88009470
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420200 -- Engineering-- Facilities
Equipment
& Techniques
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
CURRENTS
DESIGN
EFFICIENCY
ELECTRIC CURRENTS
ELECTROMAGNETIC PULSES
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUIPMENT
FIBERS
OPTICAL EQUIPMENT
OPTICAL FIBERS
PERFORMANCE
PHOTOCURRENTS
PHOTODIODES
PULSES
RADIATIONS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SIGNAL-TO-NOISE RATIO