It is difficult for traditional quartz fiber to meet the requirements of multi-parameters (temperature, pressure, etc.) testing in such harsh environments as high temperature, high pressure, strong corrosion and strong electromagnetic interference. In this paper, an optical fiber growth system based on the CO2 laser- heated pedestal growth method is designed. The system is composed of optical system, high-precision control system and software system. At the same time, the influence of several factors on the growth of high-quality fibers is analyzed, which includes single-crystal fiber growth speeds, diameters and so on. The system can provide uniform and stable heat source, and has successfully grown sapphire, spinel and other ultra-high temperature optical fibers. Some of which have been applied in engineering practice. In the future, the system can also be used to grow magnesium oxide, zirconia, hafnium oxide and other ultra-high temperature optical fibers. So that it can potentially solve the application problems of optical fibers in the field of ultra-high temperature sensing such as aerospace loading and ultra-high-speed flight.
Single crystal fiber (SCF) combines the excellent instinct properties of conventional bulk laser crystals, and the special geometry advantage of active optical fibers. YAG and LuAG are proper host candidates for single crystal fiber laser with high thermal conductivity. Despite a lower thermal conductivity for pure crystal than YAG, LuAG crystal is easier to obtain homogeneous optical quality, and has a thermal conductivity nearly independent from the doping level. Micropulling- down (μ-PD) has relatively small thermal gradient, and here we use μ-PD to carry out high quality SCFs. Through the μ-PD furnace manufactured by ourselves, crystal fibers with different diameters have been grown successfully. We designed and fabricated a method to adjust the thermal distribution, and with the favor of pulling-down rate, the specific diameter can be controlled perfectly. The crystalline quality and homogeneity along the whole fiber were investigated, and LuAG SCF was confirmed to have a fine crystal quality for laser.
Chalcogenide glasses (ChGs) have a relatively small temperature coefficient of refractive index, broad transmission
range from almost visible to mid-infrared. It is suitable for precision molding. With the help of above mentioned merits,
ChGs have a vast reservoir of value in the field of military and civilian infrared imaging. However, the internal defects of
ChGs are caused by melting, cool-demoulding and annealing in a high vacuumed ampoule. The defects include the
optical inhomogeneity, chemical inhomogeneity and built-in stress which trouble the homogeneity of ChGs and directly
affect the imaging quality of infrared imaging devices. The detection and control of internal defects is a key technique. In
this paper the platform for testing, characterization and evaluation of the inhomogeneity of ChGs will be designed and
built. The appropriate testing and evaluation criteria of inhomogeneity during the preparation procedure of ChGs in the
vacuumed ampoule will be studied. The transmittance of ChGs sample is measured repeatedly. The factor of internal
multple reflection in ChGs sample is analysed and discussed. Analysis shows that the mean transmissivity of ChGs
sample (Ge28Sb12Se60) with thick of 1 cm is approximately 66% in 8 to 11 microns. The loss is less than 2.40%/cm. The
optical path difference (OPD) caused by residual stress in ChGs sample is less than 5.2 nm/cm. The results will provide a
technical support to optimize the ChGs preparation process and improve the ChGs homogeneity.
Laser operation near 1.06 μm by diode-pumped Nd:(LuxGd1-x)3Ga5O12 (Nd:LGGG, with x = 0.1) and Gd3AlxGa5-xO12 (GAGG, with x = 1) disordered crystals has been investigated. Cw oscillation with a slope efficiency as high as 61% and 230 mW output power was achieved with 400 mW absorbed power from a 1-W laser diode in Nd:LGGG. Under the same pumping conditions cw oscillation with a slope efficiency as high as 55% and 255 mW output power was achieved with 500 mW absorbed power in Nd:GAGG. Stable passive mode-locking with single- or multi-wavelength spectrum
was obtained with a semiconductor saturable absorber mirror (SAM) and a single-prism, dispersion-compensated cavity with both the samples. Fourier-limited pulses with duration ≈ 4-9 ps and output power ≈ 40 mW were generated at three well-defined laser transitions in the range 1062-1067 nm with ND:GLGG. Two-color mode-locking regime well described by Fourier-limited synchronized pulses with duration ≈ 3.7 and 5.9 ps and output power ≈ 65 mW, with wavelength separation of 1.3 nm around 1062 nm was obtained with Nd:GAGG.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.