Yunxiang Yan

Yunxiang Yan
Harbin Engineering University · College of Science

Doctor of Philosophy
Developing a Fan-shaped IFU for Solar optics. A new type of cascaded fiber scrambler for RV measurement.

About

21
Publications
2,916
Reads
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45
Citations
Additional affiliations
June 2019 - August 2019
Harbin Engineering University
Position
  • Research Assistant
Description
  • I am in Prof. Weimin Sun's group working on the R&D of FASOT.
September 2015 - June 2018
Chinese Academy of Sciences
Position
  • Research Assistant
Education
September 2015 - June 2018
Chinese Academy of Sciences
Field of study
  • Astronomy
September 2012 - March 2015
Harbin Engineering University
Field of study
  • Optical Engineering
September 2008 - June 2012
Harbin Engineering University
Field of study
  • Optics

Publications

Publications (21)
Article
In this paper, a compact strain sensor for wide range measurement is proposed and experimentally investigated. The proposed sensor is configured by jagged long period fiber grating (J-LPFG), which is fabricated by etching on two opposite sides of single mode fiber (SMF). Since the appearance of the structure seems like jag, we name it by J-LPFG. Th...
Article
Ultra-low sample consumption detection has many applications in molecular biology, bioanalytical chemistry, and medical science. In this Letter, a novel, to the best of our knowledge, simple type of ultra-low sample consumption detection method based on a whispering gallery mode is proposed as a means to realize consecutive detection with a liquid...
Article
A Mach-Zehnder interferometer, composed of two core-offset tapered joints (COTJ-MZI), is proposed and experimentally verified for high sensitivity strain sensing. The COTJ-MZI is handily fabricated by core-offset fusion splicing and tapering based on all single-mode fiber (SMF). The fiber cores form stepped cores within the COTJs. The transmission...
Article
This review focuses on the preparation methods and wide applications of optic fiber sensors based on core-offset structure. Firstly, the classification and preparation methods of core-offset structures are introduced. Then, the applications of different types of sensors based on the core-offset structure are investigated, including the measurement...
Article
Full-text available
In this paper, we propose the CO2 laser polishing method to prepare a novel type of incline plane-shaped long period fiber grating (IPS-LPFG) for strain measurement. This structure is achieved by periodic incline plane-shaped structures polished on single mode fiber. The incline plane-shaped structure introduced asymmetric thickness of the side pla...
Article
In this paper, a sensor with high strain sensitivity and low temperature crosstalk is proposed. The proposed sensor is configured by re-modulating the D-shaped long-period fiber grating (D-LPFG). D-LPFG is fabricated by CO2 laser polishing method. Re-modulation refers to etching on the D-LPFG with CO2 laser. A new resonant dip appears after re-modu...
Article
Full-text available
We investigated and prepared a chirped long-period grating for high sensitivity bending measurement. The novel fiber structure is composed of the multimode fiber (MMF) with fixed length and gradually longer single-mode fiber using the continuous splicing method. The powerful ability of refractive index modulation in the MMF renders the miniaturizat...
Preprint
We present a new method of DEEM, the direct energy encircling method, for characterising the performance of fibres in most astronomical spectroscopic applications. It's a versatile platform to measure focal ratio degradation (FRD), throughput, and point spread function (PSF). The principle of DEEM and the relation between the encircled energy (EE)...
Preprint
Focal ratio degradation (FRD) is a major contributor to throughput and light loss in a fibre spectroscopic telescope system. We combine the guided mode theory in geometric optics and a well-known model, power distribution model (PDM), to predict and explain the FRD dependence properties. We present a robust method by modifying the energy distributi...
Article
Full-text available
We present a new method of DEEM, the direct energy encircling method, for characterising the performance of fibres in most astronomical spectroscopic applications. It’s a versatile platform to measure focal ratio degradation (FRD), throughput, and point spread function (PSF). The principle of DEEM and the relation between the encircled energy (EE)...
Article
Full-text available
Focal ratio degradation (FRD) is a major contributor to throughput and light loss in a fibre spectroscopic telescope system. We combine the guided mode theory in geometric optics and a well-known model, the power distribution model (PDM), to predict and explain the FRD dependence properties.We present a robust method by modifying the energy distrib...
Conference Paper
Full-text available
The light from out space is very weak and to guide the light into the optical fiber efficiently in astronomical spectrum telescope is of great importance for spectrum analysis. And the FRD of optical fiber can also decrease the utilization of the light of celestial body for the expending diameter of the out spot from the optical fiber, which makes...
Conference Paper
Full-text available
To measure the focal ratio degradation of astronomical fibers, we use laser as the light source which can do with bringing the light to a focal point and we can control the injection position. The laser has a high coherency and there are a number of modes in the large-core fiber. Consequently, the output spot will be a speckle. The presence of spec...
Conference Paper
Full-text available
When we use laser to measure the focal ratio degradation of astronomical fibers, we have to reduce the speckle contrast to fit the output spot to a 2-D Gaussian-like function. The origin speckle contrast is near to 100%. The simple average method doesn’t work because the speckle patterns are stable. We tried several ways to disturb randomly the tra...
Article
Full-text available
Laser is a usual light source in many measurement applications, because it has good coherence. To measure the light transmission of a large-core fiber, we designed and setup a testing system using a He-Ne laser. The light from the laser could be focused to an ideal point to incident the fiber. On the other hand, the output spot from the fiber suffe...
Article
Full-text available
The focal ratio degradation (FRD) properties of optical fibers in the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) caused by different stress were investigated by employing an Energy Distribution Method (EDM). We analyzed the FRD in two conditions with uniform stress and non-uniform stress. The qualitative and quantitative anal...
Article
Full-text available
An energy distribution method was used to calculate the focal ratio, verifying the feasibility of this method by testing of optical fiber's input and output focal ratio to determine the appropriate encircled energy (EE) in practical application. This method had good repeatability, and it provided an effective way for quantitative research of the fo...
Conference Paper
The situation was discussed when the input light is in noncentral incidence theoretically and experimentally. An optical system was built to detect the output light spot and its changes under different radial direction conditions. Fiber disturbing mode and Two Dimensional Fitting method were used here to improve the spot images captured by CCD came...

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Projects

Project (1)
Project
FASOT: Fiber Arrayed Solar Optical Telescope. Two IFU heads with 4032*2=8064 fibers in total. R~110000.