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FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme.

Cui J, Hu Y, Feng K, Li J, Tan J - Sensors (Basel) (2015)

Bottom Line: To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out.The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%.Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

View Article: PubMed Central - PubMed

Affiliation: Institute of Ultra-precision Optoelectronic Instrument Engineering, Science Park, Harbin Institute of Technology, No. 2 Yikuang Street, Nangang District, Harbin 150080, China. cuijiwen@hit.edu.cn.

ABSTRACT
In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

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Schematic diagram of the I/V converter.
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sensors-15-16516-f008: Schematic diagram of the I/V converter.

Mentions: The feedback resistor and the input capacitance produce a pole in the I/V converter’s loop transmission that can result in peaking and instability, so it is necessary to add a compensation capacitor CF to create a zero point in the loop transmission that could compensate the effect of the pole and reduce the signal bandwidth as shown in Figure 8. The stable bandwidth attainable with the preamp is a function of the gain bandwidth product of the amplifier (1.6 MHz), RF, and the total capacitance at the amplifier’s summing junction, CIN. For this circuit, the FGA01FC photodiode has a maximum capacitance of CD = 2 pF. The AD795 common-mode input capacitance is CM = 2.2 pF, and the differential-mode input capacitance is CD = 2 pF. Therefore, the total input capacitance is CIN = 6.2 pF. The signal bandwidth resulting in a 45° phase margin, f(45), is defined by:(15)f(45)=fCR2π×RF×CIN=1.6 MHz2π×100 kΩ×6.2 pF=0.64 MHz


FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme.

Cui J, Hu Y, Feng K, Li J, Tan J - Sensors (Basel) (2015)

Schematic diagram of the I/V converter.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541891&req=5

sensors-15-16516-f008: Schematic diagram of the I/V converter.
Mentions: The feedback resistor and the input capacitance produce a pole in the I/V converter’s loop transmission that can result in peaking and instability, so it is necessary to add a compensation capacitor CF to create a zero point in the loop transmission that could compensate the effect of the pole and reduce the signal bandwidth as shown in Figure 8. The stable bandwidth attainable with the preamp is a function of the gain bandwidth product of the amplifier (1.6 MHz), RF, and the total capacitance at the amplifier’s summing junction, CIN. For this circuit, the FGA01FC photodiode has a maximum capacitance of CD = 2 pF. The AD795 common-mode input capacitance is CM = 2.2 pF, and the differential-mode input capacitance is CD = 2 pF. Therefore, the total input capacitance is CIN = 6.2 pF. The signal bandwidth resulting in a 45° phase margin, f(45), is defined by:(15)f(45)=fCR2π×RF×CIN=1.6 MHz2π×100 kΩ×6.2 pF=0.64 MHz

Bottom Line: To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out.The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%.Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

View Article: PubMed Central - PubMed

Affiliation: Institute of Ultra-precision Optoelectronic Instrument Engineering, Science Park, Harbin Institute of Technology, No. 2 Yikuang Street, Nangang District, Harbin 150080, China. cuijiwen@hit.edu.cn.

ABSTRACT
In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

Show MeSH