Few-Mode Fiber Temperature Sensors Based on Modal Interference Between Orbital Angular Momentum Modes

Yueyu Xiao; Ying Tang; Zhaohui Zhu

doi:10.3788/LOP202158.0906003

Journals >Laser & Optoelectronics Progress >Volume 58 >Issue 9 >Page 0906003 > Article

Laser & Optoelectronics Progress
Vol. 58, Issue 9, 0906003 (2021)

Few-Mode Fiber Temperature Sensors Based on Modal Interference Between Orbital Angular Momentum Modes

Yueyu Xiao^*, Ying Tang, and Zhaohui Zhu

Author Affiliations

Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai University, Shanghai 200444, China

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DOI: 10.3788/LOP202158.0906003 Cite this Article Set citation alerts

Yueyu Xiao, Ying Tang, Zhaohui Zhu. Few-Mode Fiber Temperature Sensors Based on Modal Interference Between Orbital Angular Momentum Modes[J]. Laser & Optoelectronics Progress, 2021, 58(9): 0906003 Copy Citation Text

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Abstract

A temperature sensor based on orbital angular momentum (OAM) modal interference is proposed, which demodulates the information using the image detection method. The sensing mechanism and demodulation principle of the sensor are studied, and the sensing performance and immunity to light-noise are analyzed. The simulation results show that the temperature can be demodulated by a single image using the phase information carried by the OAM modes. Moreover, the demodulated result is linearly dependent on the modal phase difference. The temperature sensitivity of the sensor is immune to the fluctuation of the modal intensity and external light-noise. The proposed OAM modal interference sensor has better stability and reliability than conventional modal interference sensor based on LP modes.

Keywords

few-mode fiber fiber optics modal interference orbital angular momentum temperature sensing

\{\begin{array}{l} ψ_{11}^{e v e n} (r, θ, z) = f_{11} (r) c o s θ e x p (- j β_{11} z) \\ ψ_{11}^{o d d} (r, θ, z) = f_{11} (r) s i n θ e x p (- j β_{11} z) \end{array}

，（1）

\{\begin{array}{l} ψ_{21}^{e v e n} (r, θ, z) = f_{21} (r) c o s 2 θ e x p (- j β_{21} z) \\ ψ_{21}^{o d d} (r, θ, z) = f_{21} (r) s i n 2 θ e x p (- j β_{21} z) \end{array}

，（2）

\frac{U_{x 1} J_{x + 1} (U_{x 1})}{J_{x} (U_{x 1})} = \frac{W_{x 1} K_{x + 1} (W_{x 1})}{K_{x} (W_{x 1})} \begin{matrix} , & x = 1,2 \end{matrix}

，（3）

U_{x 1} = a \sqrt[]{k_{0}^{2} n_{1}^{2} - β_{x 1}^{2}}

，（4）

W_{x 1} = a \sqrt[]{β_{x 1}^{2} - k_{0}^{2} n_{2}^{2}}

，（5）

ψ_{+ 1} = ψ_{11}^{e v e n} + j ψ_{11}^{o d d} = f_{11} (r) e x p (j θ) e x p (- j β_{11} z)

，（6）

ψ_{+ 2} = ψ_{21}^{e v e n} + j ψ_{21}^{o d d} = f_{21} (r) e x p (j 2 θ) e x p (- j β_{21} z)

，（7）

\begin{array}{l} I (r, θ) = (A_{1} ψ_{1} + A_{2} ψ_{2}) {(A_{1} ψ_{1} + A_{2} ψ_{2})}^{*} = \\ {|A_{1}|}^{2} f_{11}^{2} (r) + {|A_{2}|}^{2} f_{21}^{2} (r) + 2 A_{1} A_{2} f_{11} (r) f_{21} (r) c o s (θ + Δ β L) \end{array}

，（8）

\begin{array}{l} F (r_{0}) = \int_{0}^{2 π} I (r_{0}, θ) c o s (θ + φ_{0}) d θ = \int_{0}^{2 π} [{|A_{1}|}^{2} f_{11}^{2} (r_{0}) + {|A_{2}|}^{2} f_{21}^{2} (r_{0})] c o s (θ + φ_{0}) d θ + \\ \int_{0}^{2 π} 2 A_{1} A_{2} f_{11} (r_{0}) f_{21} (r_{0}) c o s (θ + Δ β L) c o s (θ + φ_{0}) d θ = 2 π A_{1} A_{2} f_{11} (r_{0}) f_{21} (r_{0}) c o s (Δ β L - φ_{0}) \end{array}

，（9）

F (r_{0})_{m a x} = 2 π A_{1} A_{2} f_{11} (r_{0}) f_{21} (r_{0})

。（10）

n (T) = n (T_{0}) [1 + η (T - T_{0})]

，（11）

I (r, θ) = (A_{1} ψ_{1} + A_{2} ψ_{2}) {(A_{1} ψ_{1} + A_{2} ψ_{2})}^{*} = {|A_{1}|}^{2} f_{01}^{2} (r) + {|A_{2}|}^{2} f_{02}^{2} (r) + 2 A_{1} A_{2} f_{01} (r) f_{02} (r) c o s (Δ β L)

，（12）

S = {\frac{d I}{d T}|}_{r = 0} = - 2 A_{1} A_{2} f_{01} (0) f_{02} (0) s i n (Δ β L) L \cdot \frac{d Δ β}{d T}

。（13）

S = L \cdot \frac{d Δ β}{d T}

，（14）

Yueyu Xiao, Ying Tang, Zhaohui Zhu. Few-Mode Fiber Temperature Sensors Based on Modal Interference Between Orbital Angular Momentum Modes[J]. Laser & Optoelectronics Progress, 2021, 58(9): 0906003

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