All-optical vector magnetic field sensor based on a side-polished two-core fiber Michelson interferometer

Area of Science:

• Optoelectronics
• Fiber optics sensors
• Magnetometry

Background:

• Fiber optic sensors offer advantages like immunity to electromagnetic interference and remote sensing capabilities.
• Michelson interferometers (MI) are widely used for sensing applications due to their sensitivity.
• Developing compact, high-sensitivity magnetic field sensors remains a key challenge in various fields.

Purpose of the Study:

• To develop and demonstrate a novel magnetic field sensor.
• To investigate the performance of a side-polished two-core fiber (SPTCF)-based Michelson interferometer (MI) for magnetic field sensing.
• To evaluate the sensor's sensitivity, stability, and directional sensing capabilities.

Main Methods:

• A Michelson interferometer (MI) was constructed using a standard single-mode fiber (SMF) and a side-polished two-core fiber (SPTCF) section.
• The polished region of the SPTCF was coated with magnetic fluid to enable magnetic field detection.
• The sensor's response to magnetic field intensity was measured by monitoring changes in the evanescent field and refractive index (RI).

Main Results:

• The developed SPTCF MI sensor demonstrated vector magnetic field sensing capabilities with a highest directional sensitivity of 55.2 pm/degree.
• A sensitivity of 1.262 nm/mT was achieved when the magnetic field was parallel to the side-polished plane, within the 0-5 mT range.
• The sensor exhibited minimal temperature influence over a range of 20-85 °C, indicating high stability.

Conclusions:

• The developed side-polished two-core fiber (SPTCF)-based Michelson interferometer (MI) is a promising technology for magnetic field sensing.
• The sensor offers advantages such as low cost, simple structure, high stability, and strong anti-interference ability.
• This sensor is well-suited for diverse potential applications requiring accurate and reliable magnetic field detection.