Characteristics Of Distributed Feedback Quantum Dots Lasers On The Fiber Sidewall

In recent years,with the rapid development of micro-nano optics,high performance micro-cavity lasers have become the key research direction in this field.The distributed feedback lasers are the most promising micro-cavity lasers due to the wide emission spectrum,low threshold,good monochromism,high directional output,small size,simple manufacturing process and high integration.With the further research of distributed feedback lasers,researchers found that this kind of micro-cavity lasers have wide range of applications in biological detection,optical imaging,optical sensing,optical anti-counterfeiting,and optical chip.The emission direction of the distributed feedback laser is limited by the diffraction conditions,and the light confinement only occurs along the direction which is orthogonal to the grating line.To a certain extent,the semi-divergence beam limits the application of the distributed feedback lasers.The distributed feedback lasers integrated on optical fiber can overcome the constraints of the divergence angle due to the grating diffraction conditions,realize the laser emission with a small divergence angle based on the waveguide effect.At present,most researches focus on the distributed feedback laser on the fiber facet,but the similar fiber sidewall also has a large design space,which can greatly improve the integration of the optical system and expand its application fields.The main research direction of this thesis is the study of characteristics of the distributed feedback quantum dots lasers on the fiber sidewall.The main research content of this thesis are as follows:1.The fiberized of distributed feedback quantum dots lasers.According to the optimize parameters,the distributed feedback quantum dots lasers are fabricated on the optical fiber sidewall,to realize the directional emission of micro-cavity lasers.(1)Distributed feedback quantum dots laser on optical fiber sidewall based on sticking membrane method.The cavity of distributed feedback quantum dots laser is fabricated on polymer membrane to prepare the free-standing membrane laser,which is attached to the sidewall of the fiber to realize the laser emission with the threshold of 44.8μJ/cm~2.Two-dimensional distributed feedback gratings are fabricated on the sidewall of fiber,to realize the fiberized of two-color distributed feedback lasers.(2)Distributed feedback quantum dots laser on optical fiber sidewall based on dip coating method.We use the dip coating method to directly fabricate the distributed feedback quantum dots laser on the optical fiber sidewall,optimized the structure of cavity,realize the directional emission from fiber facet.The threshold is32.5μJ/cm~2,the linewidth is 1.1 nm,and the divergence angle is 24 mrad.2.The study on characteristics of the directional emission of distributed feedback quantum dots lasers from optical fiber facet.A distributed feedback cavity is assembled on the sidewall of the optical fiber by using dip coating method.The directional lasing is detected from the fiber facet due to the coupling effect between the mode of distributed feedback laser and the optical fiber.An analytical approach based on the Bragg condition and the coupled-wave theory was developed to explain the characteristics of the laser device.And the quantitative relationship between the coupling efficiency and the coupling coefficient of the laser mode is given.These results afford opportunities to integrate different distributed feedback lasers on the same optical fiber sidewall,achieving dual-wavelength self-aligned distributed feedback lasers for a directional emission from fiber facet.The directional emission from fiber facet is used as light source to realize the imaging of the distributed feedback laser.