US 8,896,302 B1Granted

Method for measuring magnetic induction intensity of magnetic field using short cavity fiber laser

AssigneeBeijing Information Science & Technology University

InventorsLianqing Zhu, Fei Luo, Yinmin Zhang, Wei He, Mingli Dong, Xiaoping Lou, Yudong Jia

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Abstract

A method for measuring magnetic induction intensity of a magnetic field using a short cavity fiber laser, includes the steps of: a) arranging the short cavity fiber laser, where the short cavity laser has sequentially coupled laser diode pumping source, a wavelength division multiplexer, a fiber Bragg grating, an active optical fiber and a loop mirror; b) fixing the short cavity fiber laser on a magnetostrictive material; c) disposing the short cavity fiber laser and the magnetostrictive material in the magnetic field to be measured, and matching the stretching direction of the magnetostrictive material with the direction of the magnetic field to be measured; d) measuring the drift amount of longitudinal mode output by the short cavity fiber laser; and e) calculating the magnetic induction intensity of the magnetic field to be measured.

Claims6

Dependent claims

A method for measuring magnetic induction intensity of a magnetic field using a short cavity fiber laser, comprising the steps of:

a) providing the short cavity fiber laser, comprising:
a laser diode pumping source;
a wavelength division multiplexer connected to the laser diode pumping source;
a fiber Bragg grating connected to the wavelength division multiplexer;
an active optical fiber connected to the fiber Bragg grating;
and
a loop mirror connected to the active optical fiber;
b) fixing the short cavity fiber laser on a magnetostrictive material;
c) disposing the short cavity fiber laser and the magnetostrictive material in the magnetic field to be measured to match a stretching direction of the magnetostrictive material with a direction of the magnetic field to be measured;
d) measuring a drift of a longitudinal mode of the short cavity fiber laser;
and
e) calculating the magnetic induction intensity corresponding to the drift of the longitudinal mode from an equation of:
Δ
⁢
⁢
λ
B
=
0.78
⁢
k
⁢
⁢
λ
B
k
′
⁢
H
0
,
wherein ΔλB represents the drift of the longitudinal mode, λB represents the longitudinal mode, H0 represents the magnetic induction intensity of the magnetic field, k represents the sensitivity coefficient of the magnetostrictive material, and
k
′
=
E
f
⁢
⁢
2
⁢
A
f
⁢
⁢
2
⁢
L
1
+
E
f
⁢
⁢
1
⁢
A
f
⁢
⁢
1
⁢
L
2
E
f
⁢
⁢
2
⁢
A
f
⁢
⁢
2
⁢
L
m
,
wherein Ef1 and Ef2 represent elastic modulus of the fiber Bragg grating and the active optical fiber respectively, Af1 and Af2 represent the sectional area of the fiber Bragg grating and the active optical fiber respectively, L1 represents the length of the fiber Bragg grating, L2 represents the length of the active optical fiber, and Lm represents the length of the magnetostrictive material.

77 more elements

Dependencies are inferred from the claim text.