In-fiber Integrated SPR Sensor

The optic phenomenon of surface plasmon resonance is widely used in the area of analyzing biological material and detecting environment.Optic fiber SPR sensor probe has an advantage of miniaturization because the probe can directly be immersed in the sample solution,compared with the trouble that sample solution is delivered to the SPR sensor probe with space prism structure by liquid treatment system.However,optic fiber SPR sensor has a series of disadvantages such as difficulty in realizing commercialization,low sensitivity,the difficulty in adjusting the incidence angle of resonance and realizing multi-channel measurement.Using the light path and optical devices integrated into a single fiber,forming a series of model,micro and special optical devices of the fiber optical integrated core idea.In this paper,we conducted an investigation of multi-core optic fiber SPR sensor to increase sensitivity of single mode optic fiber SPR,realize the adjustment of dynamic ranges by grinding technology,realize the multi-channel measurement by multi-core fiber SPR wavelength division multiplexing(WDM)technology and time division multiplexing(TDM)technology to solve the urgent problems in fiber SPR study.1.We fabricated the multi-mode fiber SPR probe and builded an experimental test system of fiber SPR.We found that resonance curve was formed by the superposition of several resonance curves stimulated from several angles,the sensitivity and accuracy of sensor are disturbed.We firstly proposed single mode SPR probe with cone angel structure to greatly increase the sensitivity of optic fiber SPR sensor.We adjusted the incidence angle of SPR light source by changing the grinding angle to adjust the sensitivity of optic fiber SPR sensor and dynamic range change law.On this basis,we proposed multicore optic fiber reflection-type SPR sensor probe on the end surface,combined the sensor and microfluidic chip and realize the real-time monitoring of refractive index of flowing liquid in the microfluildic channel.Especially,the sensitivity reached 5213nm/RIU.2.(1)Transmission WDM:We proposed distributed cascade SPR sensor based on excentric core fiber.When the two grinding angles are 9° and 17°,the range of refractive index is between 1.333 and 1.385,with the mean sensitivity of 2826nm/RIU and 4738nm/RIU,respectively.(2)Reflective WDM:We proposed two core optic fiber reflective distribution type SPR sensor with cone angle.The microfluidic device,which simulates blood and tissue outside the vessel,was made by elastic microfluidic material PDMS to conduct test.3.We firstly proposed multi-core optic fiber multi-channel SPR sensor by time division multiplexing technique.(1)Transmission optic fiber SPR time division multiplexing technique:Every fiber core of multicore optic fiber was regarded as a sensor region.The light was injected into every fiber core to realize the independent multichannel sense in the corresponding sense region of every fiber core.(2)Reflective optic fiber SPR time division multiplexing technique:Three pair symmetric structures with cone angle were made by optic fiber grinding technology on the end face of seven core optic fiber to form reflection-type multi-channel SPR sensor with three channel.4.The investigation of optic fiber SPR multi-channel mix technology.(1)We firstly proposed and fabricated two core optic fiber SPR sensor with four channel.The two core optic fiber was divided into two roads by time division multiplexing technique(in parallel)and then we realized the two channels by use of wavelength division multiplexing technique(cascade)on the every road.(2)The multichannel optic fiber SPR sensor was fabricated by the multi-core optic fiber time division multiplexing technique.A cascade of traditional transmission optic fiber SPR sense fiber was made on the receiving optic fiber and we combined the wavelength division multiplexing technology and time division multiplexing technology in order to double the number of multicore optic fiber channel.(3)We deeply investigated the effect of film thickness on sensitivity of optic fiber SPR and dynamic change range.SPR reflection light on the single mode optic fiber structure with cone angle was injected into 125 ?m step refractive index plastic cladding optic fiber and transmission-type optic fiber SPR sensor was made on the plastic cladding optic fiber to realize the distribution-type sensor of optic fiber SPR.Continuous adjustment of SPR dynamic range was realized by the change of grinding angle and film thickness on the two cascades of SPR sensor,which can dissolve the problem of difficulty in distinguishing the two resonance valley in the limited wavelength detecting range of distribution optic fiber SPR sensor.In conclusion,we proposed single mode optic fiber SPR probe with practicability and effectively improved SPR sensitivity of optic fiber.We conducted the investigation of optic fiber SPR wavelength division multiplexing technology and time division multiplexing technology,firstly proposed and verified the program of combing SPR wavelength division and time division multiplexing technology in the multicore optic fiber to promote the development of optic fiber SPR multichannel practical technology.We firstly conducted the survey of mix-technology optic fiber SPR multichannel technology.We used PDMS to form microfluidic chip and combined microfluidic chip and multicore optic fiber SPR probe to simulate blood test.In-fiber integrated SPR sensors in a single fiber integrated multiple SPR sensor,an effective solution to the optical fiber SPR sensor sensitivity is low,and the resonance angle adjustment difficulties,realize multi-channel measurement difficulties and other issues.