Research On Optical Fiber Sensing Techniques And Its Applications In Biochemical Field

The biosensor had caused wide attention and soon became a hot study area since it put forward for the first time in 1962.It had been widely used in biological detection and make a large contribution to the development of life science.With the development of biotechnology,we can detect not only glucose but also cells,microorganism,Antigen-antibody,or cancer cells with high accuracy.In recent decades,the progress of the optoelectronic technology was a sizable boost for the development of biosensor.Since light is very sensitive to the external environment,the dynamic change of biological assays could be expressed by optical signal.This article studies the optical fiber sensing techniques and its applications in biochemical field,involves the main content includes: a concentration sensor of streptavidin based on optical fiber,a fiber optic liquid level sensor used in large tank and a Two cascading abrupt-tapers optical fiber modal interferometer based angle sensor.In this paper,the study reads as follows:First,we proposed a streptavidin concentration sensor by the combination of the biotechnology and optical fiber sensing technology.The characteristic of the surface of optical fiber is changed through layer-by-layer self assembly technology or using silane coupling agents.A novel biotin-advin conjugation fiber probe was synthesized and employed in the detection of streptavidin.The fiber probe is made by normal single mode fiber,long period fiber grating or post-corrosion fiber Bragg grating to be a sensitive part.We can get the concentration of streptavidin by monitoring the change of spectrum.We also exerted some artificial interference to verify the specific binding of biotin-advin system,the initial experiments demonstrated that the biotin have excellent absorbency to streptavidin,which means it is feasible to measure the concentration of streptavidin by this fiber sensor,showing a good application prospect in antigen and antibody detection or cancer cells examination.Then,a liquid-level sensor based on fiber Bragg gratings with plastic corrugated pipe is proposed and experimentally demonstrated.Liquid level sensing is widely used in chemical industry,the solution in storage tank may be strongly acidic,alkaline or sometimes it is toxic and caustic so they should be monitored every time.In this paper,we propose and experimentally confirm a compact liquid-level sensor based on fiber Bragg gratings with a plastic corrugated pipe,when liquid level changes,the fiber Bragg grating will experience same tension as plastic corrugate pipe produced by fluid pressure.The liquid level can be evaluate by measuring the wavelength shift of Bragg wavelength.It is worth nothing that the performance of the proposed sensor is highly dependent on the plastic corrugate pipe elastic coefficient.There was no doubt that a pipe with a more proper elastic coefficient,our system would have a longer measurement distance and a higher resolution.