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This paper presents a circuit for simultaneous reception of optical power and data using a solar cell. The circuit employs a switched-inductor boost DC-DC converter for energy harvesting and a low-power thresholding receiver for data reception. The thresholding data receiver comprises a current-sense resistor that monitors the current output of the solar cell, an instrumentation amplifier, a band-pass filter and a comparator. A system-level analysis of an optical communication system employing the proposed circuit is presented along with a circuit-level analysis and implementation. As a proof-of-concept, the proposed circuit for simultaneous power and data reception is implemented using off-the-shelf components and tested using a custom-built test setup. Measurement results, including harvested power, electronic noise and bit error rate (BER), are reported for a GaAs solar cell and a red LED light source. Results show that 223 μW of power are harvested by the DC-DC converter at a distance of 32.5 cm and a radiated power of 9.3 mW. At a modulation depth of 50% and a transmission speed of 2.5 kbps, a BER of 1.008×10^-3 is achieved. Measurement results reveal that the proposed solution exhibits a trade-off between harvested power, transmission speed and BER. 

This paper presents a single-aperture, single-pixel reader for communication with Optical Frequency Identification (OFID) tags. OFID tags use solar cells to transmit and receive information wirelessly as well as to harvest radiant energy. Due to its single-aperture architecture, the reader's optical system provides a shared optical path for reception and transmission. Also, physical alignment between the reader and an OFID tag is visually guided using the reader's emitted light, securing a robust data link as long as the OFID tag is illuminated. In this paper, a description of the reader's optical and electronic sub-systems are presented. The transmitter and receiver circuits are described in detail. The transmitter, built with a linear LED driver, achieves a power efficiency of nearly 87%. The receiver, featuring a third-order bandpass filter, reduces both low-frequency and high-frequency ambient noise. A prototype of the reader was fabricated and housed in a custom 3D-printed enclosure. Test results show that the reader is able to receive modulated luminescent signals from an OFID tag at a distance of 1 m and at a data rate of 3 kbps. 

An optical wireless communication approach that exploits the photo-luminescent radiation of LEDs is presented. In this approach the photo-luminescence of an array of LEDs is modulated by varying the impedance connected to the LEDs. The LEDs are also employed to harvest radiant energy making possible fully passive optical communications tags. Possible applications of this approach include short-range underwater communications. Initial experimental results suggest that communication speeds of few kilobits per second can be achieved. 

This paper presents a wireless temperature sensor that uses a GaAs solar cell as a wireless transmitter of information. Transmission of information with a solar cell is possible by modulating the luminescent radiation emitted by the solar cell. This technique, dubbed Optical Frequency Identification or OFID, was recently reported in the literature and in this work is used to transmit temperature measurements wirelessly. The hardware design of an OFID temperature sensor tag and its corresponding reader is described. A prototype of the proposed sensor was built as a proof of concept. Experimental results demonstrate wireless data transmission at a distance of 1 m distance and at a bit rate of 1200 bps. The wireless temperature sensor has a maximum error of 0.39°C (after calibration) with respect to a high-precision temperature meter. 

Modulation of the luminescent radiation of a GaAs solar cell to transmit information wirelessly is explored. The impulse response is measured to determine the transmission speed of binary symbols using square pulses. 

High-efficiency solar cells, such as GaAs solar cells, exhibit strong luminescent emissions in the infrared. This paper presents two circuits that are able to modulate these luminescent emissions while harvesting energy from the solar cell. These circuits can be used in Internet-of-Things applications where devices need an energy source and a means to transmit information wirelessly. The proposed circuits are based on a boost DC-DC converter and are suitable for binary (on-off) modulation. These circuits require only minimal additional hardware (either a switch or an AND gate) for their implementation. Proof-of-concept prototypes of these circuits were built and tested. Experimental results show a tradeoff between harvested energy and bit error rate.