Suzhou, China
Suzhou, China

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Liu H.,Hebei University of Science and Technology | Su Y.,Hebei University of Science and Technology | Yao X.S.,Hebei University of Science and Technology | Yao X.S.,General Photonics Corporation | And 2 more authors.
2016 Conference on Lasers and Electro-Optics, CLEO 2016 | Year: 2016

We demonstrate using optical coherence tomography (OCT) to inspect the surface topography of solar cells and evaluated the light trapping efficiencies in different stages of production process. © 2016 OSA.


Su Y.,Precision Information | Steve Yao X.,Precision Information | Steve Yao X.,General Photonics Corporation | Li Z.,Precision Information | And 5 more authors.
Biomedical Optics Express | Year: 2015

We present detailed measurement results of optical attenuation’s thermal coefficients (referenced to the temperature of the skin surface) in different depth regions of in vivo human forearm skins using optical coherence tomography (OCT). We first design a temperature control module with an integrated optical probe to precisely control the surface temperature of a section of human skin. We propose a method of using the correlation map to identify regions in the skin having strong correlations with the surface temperature of the skin and find that the attenuation coefficient in these regions closely follows the variation of the surface temperature without any hysteresis. We observe a negative thermal coefficient of attenuation in the epidermis. While in dermis, the slope signs of the thermal coefficient of attenuation are different at different depth regions for a particular subject, however, the depth regions with a positive (or negative) slope are different in different subjects. We further find that the magnitude of the thermal coefficient of attenuation coefficient is greater in epidermis than in dermis. We believe the knowledge of such thermal properties of skins is important for several noninvasive diagnostic applications, such as OCT glucose monitoring, and the method demonstrated in this paper is effective in studying the optical and biological properties in different regions of skin. © 2015 Optical Society of America.


Su Y.,Tianjin University | Meng Z.,Tianjin University | Meng Z.,Suzhou Optoring Ltd. Co. | Wang L.,Tianjin University | And 4 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014

The living human skin has complex composition of tissue in several distinctive layers with various thicknesses, and different tissues have different glucose dependence of optical properties. Therefore, the calculation analysis method to find the maximum correlation region containing minimum noise to be used for calibration is worth being concerned in noninvasive blood glucose monitoring. We report an algorithm using correlation analysis to calculate the depth of region, which has the maximum correlation between blood glucose concentration and tissue optical properties. The selected correlation region also has the least noise interference from other skin layers. This method can improve the prediction precision of the noninvasive blood glucose concentration measuring and has a value for application.


Su Y.,Hebei University of Science and Technology | Yao X.S.,Hebei University of Science and Technology | Yao X.S.,General Photonics Corporation | Wei C.,Hebei University of Science and Technology | And 3 more authors.
IEEE Photonics Journal | Year: 2016

We use optical coherence tomography (OCT) to systematically study the dependence of the optical attenuation coefficient μt upon the applied pressure P in different depth regions of the human skin in vivo. We find that the same OCT data can be used to estimate thicknesses of the epidermis layer and the epidermis-dermis junction and obtain the thickness changes in these skin layers induced by the pressure. We further propose and demonstrate using the correlation map to identify depth regions in which μt has positive and negative correlations with the applied pressure and study in detail the changes of μt in dermis with the applied pressure. By using a low-cost thin-film pressure sensor to monitor the applied pressure accurately, we are able to quantitatively obtain the pressure dependence of μt in different skin layers in vivo with the following interesting findings: When a pressure ranging from 0 to 20 kPa is applied on the volar side of the forearm skin, μt increases with the applied pressure in the epidermis layer, which coincides with the thickness decrease and increase of the epidermis and the epidermis-dermis junction, respectively. In contrast, μt decreases with applied pressure in the upper dermis but increases again in the deeper dermis with applied pressure. Our results demonstrate that the OCT correlation map and the thin-film sensor are effective tools to study the optical scattering properties of human skin under pressure. We anticipate that our experimental and analytical methods reported in this paper can be useful for clinical diagnostic applications, such as noninvasive blood glucose monitoring. © 2009-2012 IEEE.


Su Y.,Tianjin University | Meng Z.,Tianjin University | Meng Z.,Suzhou Opto ring Co. | Wang L.,Tianjin University | And 3 more authors.
Chinese Optics Letters | Year: 2014

Noninvasive glucose monitoring (NIGM) techniques based on optical coherence tomography (OCT) are affected by several perturbing factors, including variation of tissue temperature. We first design a temperature control module integrated with an optical scanning probe to precisely control the temperature of skin tissues. We investigate the influence of temperature on NIGM with OCT by correlation analysis at different depths of in vivo human skin. On average, the relative changes in attenuation coefficient (μt) per 1℃ of temperature lead to 0.30 ± 0.097 mmol/L prediction error of blood glucose concentration. For NIGM measurement methods using optical properties of the tissues, this effect can be taken into account. © 2014 Chinese Optics Letters.


Li Z.,Tianjin University | Li Z.,Suzhou Opto ring Co. | Meng Z.,Tianjin University | Wang L.,Tianjin University | And 4 more authors.
IEEE Photonics Technology Letters | Year: 2015

We report the first study of using optical coherence tomography (OCT) to inspect the winding quality of fiber optical gyro coils. We use a swept-source OCT system to scan a quadrupole-wind fiber coil for obtaining its two-dimensional and three-dimensional (3D) tomographic images. The defects beneath the surface of the fiber coil, which otherwise are invisible by video inspection, can be clearly identified with such tomographic images. The winding quality of each layer can also be independently visualized with the reconstructed 3D images from different angles or in different sections. We believe that the proposed method will be useful to ensuring the quality production of each and every fiber gyro coil. © 2014 IEEE.


Li Z.,Tianjin University | Li Z.,Suzhou Opto Ring Co. | Meng Z.,Tianjin University | Meng Z.,Suzhou Opto Ring Co. | And 2 more authors.
Optics Express | Year: 2013

We introduce a parameter called pointing error thermal sensitivity (PETS) for quantitatively determining the quality of a quadrupolar (QAD) fiber coil under radial temperature variations. We show both analytically and experimentally that the pointing error of a fiber gyro incorporating the fiber coil is linearly proportional to the final radial thermal gradient on the coil, with PETS as the proportional constant. We further show that PETS is linearly proportional to another parameter called effective asymmetric length of the coil. By thermally inducing different radial thermal gradients on the fiber coil and measuring the corresponding pointing errors in a gyroscopic measurement setup, we can confidently determine the PETS of the fiber coil and its associated effective asymmetric length caused by imperfections in coil winding. Consequently, we are able to precisely trim the coil to achieve best thermal performance. © 2013 Optical Society of America.


Wang L.,Tianjin University | Meng Z.,Tianjin University | Yao X.S.,Tianjin University | Liu T.,Tianjin University | And 2 more authors.
IEEE Photonics Technology Letters | Year: 2012

An adaptive speckle denoising method called Volume-BM3D is developed for optical coherence tomography (OCT) volume data processing, including an adaptive noise level estimation algorithm and a denoising strategy based on block-matching and filtering in a highly sparse local 3-D transform domain. Noise level estimation, an important step for denoising, is obtained from estimating signal fluctuations among neighboring A-Scans. Unlike 2-D denoising approaches, the Volume-BM3D considers the similarities of tissue structures either in a single 2-D image or in a volume data simultaneously. It not only effectively suppresses speckle noise, but also improves the visualization of small morphological features, such as sweat glands in finger images. Application of this proposed method to the OCT volume data of a human finger tip shows an 18.4-dB signal-to-noise ratio improvement in speckle noise reduction with little edge blurring. It outperforms other filtering methods in suppressing speckle noises and revealing attenuated subtle features. © 2012 IEEE.


Cao C.,Tianjin University | Meng Z.,Tianjin University | Meng Z.,Suzhou Optoring Ltd. Co. | Wang L.,Tianjin University | And 2 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2013

Cross-polarized image can provide both polarization-sensitive information and a more clear sub-surface structure of the sample. As a result, getting the cross-polarized image by using optical coherence tomography (OCT) becomes more and more popular. A novel fiber-based cross-polarized optical coherence tomography (CP-OCT) system is implemented, which is capable of acquiring both cross-polarized signal and co-polarized signal of a sample simultaneously. Forming principles of both cross-polarized and co-polarized signals are described, and the expressions of them are derived using Jones matrix. The images of a glass slide, a λ/4 wave plate at a wavelength of 1310 nm, and vivo skin obtained with the system confirm that CP-OCT can provide both polarization-sensitive and polarization-insensitive informations of the sample.


Li Z.,Tianjin University | Li Z.,Suzhou Opto ring Co. | Yao X.S.,Tianjin University | Yao X.S.,General Photonics Corporation | And 5 more authors.
Journal of Lightwave Technology | Year: 2015

We present methods and processes of using a ghost-peak-free distributed polarization crosstalk analyzer (DPXA) to accurately obtain all polarization related parameters of polarization-maintaining (PM) fibers. We show that by first inducing a series equidistant periodic polarization crosstalk peaks along a PM fiber and then measuring the positions and the widths of these peaks using the analyzer, all birefringence related parameters of the PM fiber, including group birefringence, group birefringence variation along the fiber, group birefringence dispersion, and group birefringence temperature coefficient, can be accurately obtained. We further show that the DPXA has the ability to identify and eliminate polarization crosstalk contributions of connectors or splices in the measurement system and therefore can be used to obtain high accuracy measurement of the polarization extinction ratio (PER) of PM fibers. Finally, we propose a set of parameters based on the distributed polarization analysis to quantitatively evaluate the quality of PM fibers. We believe that the methods and processes described in this paper can be widely applied in the industry for the complete characterization of PM optical fibers. © 2014 IEEE.

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