An optoelectronic probe with loss compensation for electromagnetic monitoring at low frequencies

Abstract

We explore the development of an optoelectronic probe for MF/HF/VHF (up to ∼ 37 MHz) radio frequency bands able to display the complete waveforms. It was built from simple, low cost and robust components. A passive loop antenna generates RF current which modulates an ultra-bright LED of display/illumination. The light signals are transmitted along a PMMA plastic optical fibre (POF) to an optical receiver placed in a remote site. All characterization measurements were carried out in the near-field region. Far-field radio transmissions could also be detected. The probe presented at 0.5 MHz tuning-band has shown a 62 dBµV dynamic range and was able to detect down to Hmin ∼ 0.8 nA cm−1 magnetic field amplitude. A new technique for loss compensation of the fibre link is proposed and successfully tested.

Development of Infrared Optical Links Using Perfluorinated Polymeric Optical Fibres

“…In order to simplify the manufacturing, manipulation, to provide robustness and lowering the cost of low-frequency (starting at < 120 MHz) Wireless-over-Fibre (WoF) systems, since 2006 our group have been carried out probably the unique efforts on systematic development of simple systems named as "optoelectronic probes" [4]. Optoelectronic probes are useful for measurement/tracking of radio signals [4] or can be adapted to be a complete WoF links. Using PF-POFs the WoF links may be simplified to reach up to few kilometres distances.…”

Optimized Optoelectronic/RF Probe for Low- Frequency Wireless-over-Fiber Transmissions

“…The Federal Communications Commission (FCC) is opening the frequency bands used in the past for the analogue services [3] now to be used in new digital services. Another systems of interest may work at even lower frequencies as < 120 MHz [4]. The latter lower-frequency bands are also of interest for military defence as the use for many antennas remoting on ships, use of High-Frequency (HF) band on the battlefield, etc [4][5][6].…”

“…Another systems of interest may work at even lower frequencies as < 120 MHz [4]. The latter lower-frequency bands are also of interest for military defence as the use for many antennas remoting on ships, use of High-Frequency (HF) band on the battlefield, etc [4][5][6]. Many commercially available analogue fibre-optic links are designed for broadband operation and, hence, are not optimized for many narrowband or low-frequency applications.…”

“…LEDs and Resonant-Cavity LEDs (RC-LEDs) coupled to PMMA or perfluorinated POFs may be used instead of laser diodes (LDs) and single-mode silica optical fibres. POFs are easier, safer and cheaper to handle than silica fibres [4,7], specially the connection among light sources, photo-detectors and POFs. RC-LEDs generate stimulated radiation instead of spontaneous as done by LEDs [7].…”

“…II. -OPTOELECTRONIC PROBES‖ -Optoelectronic probes‖ are useful or potentially useful in many applications that require detection, measurement or tracking the waveforms and their frequency amplitude components from low to high frequencies radio signals propagating through the environment, as examples: antennas characterization, electromagnetic pollution monitoring, remote link to/from antennas, EMC tests, etc [4]. Furthermore, since 2000 there has been a growing interest in transceivers operating in low frequencies for many applications [4].…”