An interferometric fiber-optic sensor using a local laser is proposed. An Er-doped-fiber ring-laser is injection locked to a signal carrier using a fiber coupler and the extracted carrier is directly homodyned with the signal light at the output of the coupler. With a feedback loop suppressing the local laser instability, demodulation linearity over 2 decades and minimum detection in the 10-3 rad range are attained. The Er-doped fiber ring laser constructed for this work has a linewidth of less than 1.4 kHz.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics