The modulation depth, defined according to practical modulation results, which changes with the microwave power and its frequency, is significant for systems utilizing the frequency-shift characteristic of the LiNbO3 ...The modulation depth, defined according to practical modulation results, which changes with the microwave power and its frequency, is significant for systems utilizing the frequency-shift characteristic of the LiNbO3 waveguide Electro-Optic Intensity Modulator （EOIM）. By analyzing the impedance mismatch between the microwave source and the EOIM, the effective voltage applied to the RF port of the EOIM is deprived from the microwave power and its frequency. Associating with analyses of the phase velocity mismatch between the microwave and the optical wave, the theoretical modulation depth has been obtained, which is verified by experimental results. We provide a method to choose the appropriate modulation depth to optimize the desired sideband through proper transmission bias for the system based on the frequency-shift characteristic of the EOIM.展开更多
A novel dual-loop technique was proposed for single-mode selection in an optoelectronic oscillator （OEO）. It consisted of a pump laser and a feedback circuit including an intensity modulator, a Fabry-Perot （FP） et...A novel dual-loop technique was proposed for single-mode selection in an optoelectronic oscillator （OEO）. It consisted of a pump laser and a feedback circuit including an intensity modulator, a Fabry-Perot （FP） etalon, two optical fiber delay lines, two photodetectors, and an amplifier. By inserting the Fabry-Perot etalon, the proposed dual-loop OEO realized a single mode oscillation ranging from 0 Hz to 20 GHz. The strong oscillation mode was present at 15 GHz, and the side modes suppression ratio （SMSR） exceeded 140dB. More over the length of the two fiber loops were just 5 meters and 36 meters.展开更多
Abstract： The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator （PCRR） is proposed and designed for monitoring the salinity of the seawater from 0% to 100% （0 g/L to 100 g/...Abstract： The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator （PCRR） is proposed and designed for monitoring the salinity of the seawater from 0% to 100% （0 g/L to 100 g/L） at 25℃. The concentration of the salinity in the seawater changes the refractive index of the seawater. The change in the refractive index of the seawater brings the change in the output signal intensity of the sensor as the output power and mapping the salinity level, the seawater flows inside the sensor. By detecting the salinity can be evaluated. The proposed sensor is composed of periodic Si rods embedded in an air host with a circular PCRR placed between the inline quasi waveguides. Approximately, 2.69% of output power reduction is observed for every 5% （5 g/L） increase in the salinity as the seawater has a unique refractive index for each salt level. With this underlying principle, the performance of the sensor is analyzed for different temperatures.展开更多
Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups...Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Nevertheless, as optical fibers revolutionize the way of carrying data in telecommunications, a similar trend is detectable in the world of sensing. The present review aims to describe the most relevant contributions of fiber sensing in biomechanics since their introduction, from 1960s to the present, focusing on intensity-based configurations. An effort has been made to identify key researchers, research and development （R＆D） groups and main applications.展开更多
基金supported by Program for New Century Excellent Talents in University(No.NCET-06-0925)
文摘The modulation depth, defined according to practical modulation results, which changes with the microwave power and its frequency, is significant for systems utilizing the frequency-shift characteristic of the LiNbO3 waveguide Electro-Optic Intensity Modulator （EOIM）. By analyzing the impedance mismatch between the microwave source and the EOIM, the effective voltage applied to the RF port of the EOIM is deprived from the microwave power and its frequency. Associating with analyses of the phase velocity mismatch between the microwave and the optical wave, the theoretical modulation depth has been obtained, which is verified by experimental results. We provide a method to choose the appropriate modulation depth to optimize the desired sideband through proper transmission bias for the system based on the frequency-shift characteristic of the EOIM.
文摘A novel dual-loop technique was proposed for single-mode selection in an optoelectronic oscillator （OEO）. It consisted of a pump laser and a feedback circuit including an intensity modulator, a Fabry-Perot （FP） etalon, two optical fiber delay lines, two photodetectors, and an amplifier. By inserting the Fabry-Perot etalon, the proposed dual-loop OEO realized a single mode oscillation ranging from 0 Hz to 20 GHz. The strong oscillation mode was present at 15 GHz, and the side modes suppression ratio （SMSR） exceeded 140dB. More over the length of the two fiber loops were just 5 meters and 36 meters.
文摘Abstract： The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator （PCRR） is proposed and designed for monitoring the salinity of the seawater from 0% to 100% （0 g/L to 100 g/L） at 25℃. The concentration of the salinity in the seawater changes the refractive index of the seawater. The change in the refractive index of the seawater brings the change in the output signal intensity of the sensor as the output power and mapping the salinity level, the seawater flows inside the sensor. By detecting the salinity can be evaluated. The proposed sensor is composed of periodic Si rods embedded in an air host with a circular PCRR placed between the inline quasi waveguides. Approximately, 2.69% of output power reduction is observed for every 5% （5 g/L） increase in the salinity as the seawater has a unique refractive index for each salt level. With this underlying principle, the performance of the sensor is analyzed for different temperatures.
文摘Fiber optic sensors have a set of properties that make them very attractive in biomechanics. However, they remain unknown to many who work in the field. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Nevertheless, as optical fibers revolutionize the way of carrying data in telecommunications, a similar trend is detectable in the world of sensing. The present review aims to describe the most relevant contributions of fiber sensing in biomechanics since their introduction, from 1960s to the present, focusing on intensity-based configurations. An effort has been made to identify key researchers, research and development （R＆D） groups and main applications.
