A fiber Bragg grating (FBG) is one of the most common and widely used fiber optic sensors. One main issue when using a FBG-based sensor is that it is simultaneously sensitive to both the strain and the temperature, and compensation for the temperature and strain effects is necessary to measure these parameters. The available compensation techniques mean that the interrogation of FBG sensor systems is complex and make sensor networks bulky by increasing the number of sensors. Several of these compensation techniques are not feasible in in situ applications. In this paper, we propose a method for discriminating between the strain and the temperature by measuring the change in the single Bragg wavelength. Our proposed technique is based on measuring the sidelobe power, which appears adjacent to the main Bragg peak due to the strength of the interference between the forward and backward propagating waves of the Bragg grating sensor. We demonstrate by experiments that the proposed methodology can discriminate between the strain and temperature effects, making the interrogation system less complex with a very reasonable hardware cost.

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, "W-band radio-over-fiber propagation of two optically encoded wavelength channels," Opt. Eng. 57(1), 016104 (2018), doi: 10.1117/1.OE.57.1.016104. Abstract. We propose a W-band wavelength-division multiplexing (WDM)-over-optical code-division multiple access radio-over-fiber system. This system offers capacity expansion by increasing the working frequency to millimeter wave region and by introducing optical encoding and multiwavelength multiplexing. The system's functionality is investigated by software modeling, and the results are presented. The generated signals are data modulated at 10 Gb∕s and optically encoded for two wavelength channels and transmitted with a 20-km length of fiber. The received signals are optically decoded and detected. Also, encoding has improved the bit error rate (BER) versus the received optical power margin for the WDM setting by about 4 dB. In addition, the eye-diagram shows that the difference between received optical power levels at the BER of 10 −12 to 10 −3 is about 1.3% between two encoded channels. This method of capacity improvement is significantly important for the next generation of mobile communication, where millimeter wave signals will be widely used to deliver data to small cells.

The design and performance evaluation of a W-band wavelength division multiplexed-over-optical code division multiple access radio-over-fiber system are presented. The system's performance introduces expansion in the number of channels and bit rate per channel for millimeter wave signals by optically encoding signals in a multiwavelength transmission system. The performance of the system is verified based on software simulation of three channels that carry six users' encoded data. The achieved results are measured in bit-errorrate and eye-diagram figures. The obtained results are analyzed for each wavelength channels and each code families used. Bit error rates of 10 −2 to 10 −6 are obtained for channels operating at 10 Gb∕s.