Brillouin fibre-optic gyro with directional sensitivity

✍ Scribed by Yosuke Tanaka; Shigefumi Yamasaki; Kazuo Hotate

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 145 KB
• Volume: 29
• Category: Article
• ISSN: 0030-3992
• DOI: 10.1016/s0030-3992(97)88439-3

✦ Synopsis

The Brillouin fibre-optic gyro is a solid-state laser gyro, made of a fibre ring-resonator with high finesse. It utilizes the counterpropagating lasing of Stokes beams independently produced in the ring-resonator by the stimulated Brillouin scattering process. According to the Sagnac effect, the frequency difference between the counterpropagating Stokes beams shows the rotation rate applied to the ringresonator. The absolute value of this frequency difference is directly obtained as a beat note by coherently combining those two beams. However, the information on the positive or negative is lost in the process, which means no information on the rotation direction. To overcome this problem, we propose a new scheme based on the phase diversity detection, which gives a set of two beat notes with orthogonal polarization. From the phase difference between the beat notes, the rotation direction is easily recognized as well as its rate. Although the demonstrated experimental set-up includes bulk-optic components, they can be replaced by fibre-optic or integrated optic ones.