Based On Carbon Nanotube Coating Tilted Fiber Grating FWM Research

With the development of modern science and technology,the demand for network is becoming larger and larger.Multichannel and large bandwidth of communication are the methods to solve the problem of large information transmission.Because of the third order nonlinear optical properties of carbon nanotubes,there are energy exchange between laser and medium when a strong laser incident.Then the four wave mixing will happen in the medium.It will cause crosstalk between the signal wave which has the similar frequency in the communication system all though the FWM itself is weak.Contrarily we can use it to achieve wavelength conversion function if we can enhance this effect.The first half of this paper describes that development of microwave photonics which is the subject of our group,some basic knowledge of nonlinear optics and fiber gratings and carbon nanotubes.The most important content is that mainly about preparation and coating of tilted fiber gratings,and the experimental study on four wave mixing effect of carbon nanotube coating tilted fiber grating.Contents of each chapter:(1)The development of microwave photonics,nonlinear optics,fiber Bragg grating and carbon nanotubes.The basic theoretical derivation of four wave mixing,the theoretical analysis of tilted fiber gratings and basic knowledge of carbon nanotubes.(2)The preparation of tilted fiber gratings.Firstly,the preparation of high photosensitive fibers,hydrogen treatment for 14 days,then,raster writing by Phase mask method.Tilt optical fiber gratings of 2o,4o,6o,8,10 o and 12 o were fabricated by experiments.(3)Tilted fiber gratings coating with carbon nanotube.Firstly,preparing the coating liquid,secondly,silanizing the surface of fiber grating.Then,coating tilted fiber grating with the carbon nanotube.Coating 30 seconds each time,so that we can get all thickness tilted fiber.At last,the tilted fiber which angle of inclination is 2o,4o and 12 o has been coated 10 times and 30 times.The tilted fiber,angle of inclination is 6o,8oand 10 o,has been coated 10 times,20 times,30 times and 40 times.(4)The experimental study on four wave mixing effect of the carbon nanotube coating tilted fiber grating and analysis of experimental data processing.Four factors were changed in the study,which are pump wavelength,pump power,dip angle and coating thickness.Encounter problems in the process of research and solutions,and analyze the results of the study.The results show that,the optical signal-to-noise ratio of the converted signal is 10 dB,with the tilted fiber grating angle of 6o and the coating number of 30 times.