दूरसंचार प्रणाली एवं प्रबंधन

Hybrid Ring /Linear Cavity Fiber Laser Operating at 1064 nm Band for Sensing

Abstract

Shien-Kuei Liaw

Laser sources with wavelengths at around 1064 nm have many practical applications and are widely used in materials processing, display technology, biomedical engineering, and remote sensing applications [1]. The 1064 nm laser also has other applications in frequency doubling, optical coherence tomography, micromachining, optical wireless, time-resolved spectrum, etc. In the application of display technology, it is an excellent excitation source for nonlinear optics and biomedical engineering as the biological sample is usually composed of water. Lightwave at 1064 nm band is not absorbed by water or oxygen inside the tissue. Hemoglobin, deoxyhemoglobin or melanin absorption can reduce the damage of biological samples [2], and the Raman light source near the 1064 nm is an ideal light source for medical detection [3]. Semiconductor optical amplifier based hybrid ring cavity/linear cavity fiber laser can also be used as optical sensing source. Compared with conventional sensors, fiber sensors present several advantages, including high sensitivity, great mechanical stability, electromagnetic interference immunity, low cost, compactness, and easy maintenance. The proposed 1064 nm SOA based fiber laser can also play as a sensor. In a fiber-laser-based FBG sensing system, the laser cavity forms part of the FBG sensor. Therefore, the changes in the FBG physical condition can be detected directly via the laser spectrum. The dynamic range of the fiber laser sensor is equivalent to the cavity length.