We developed the extrusion method to prepare arsenic-free chalcogenide glass fibers with glass cladding. By using the double nested extrusion molds and the corresponding isolated stacked extrusion method, the utilization rate of glass materials was greatly improved compared with the conventional extrusion method. Fiber preforms with optimal stability of core/cladding ratio throughout the 160 mm length were prepared using the developed extrusion method. Typical fiber structure defects between the core/cladding interface, such as bubbles, cracks, and core diameter variation, were effectively eliminated. Ge-Sb-Se/S chalcogenide glasses were used to form a core/cladding pair and fibers with core/cladding structure were prepared by thermally drawing the extruded preforms. The transmission loss, fiber bending loss, and other optical characters of the fibers were also investigated.
The development of quantum cascade lasers that span mid-infrared wavelengths necessitate developing new infrared fibers capable of transmitting light in the 3 ‒ 12 micron range. The main material candidates for producing infrared fibers that cover this spectral region are polycrystalline silver halides and glassy tellurium-based chalcogenide glasses. The latter are more chemically stable, and thus represent a superior choice for infrared fibers. We adapt a fiber fabrication methodology that we recently developed for other chalcogenide glasses to tellurium-based chalcogenides. We introduce a novel infrared optical fiber with tellurium-based chalcogenide core and cladding, which is provided with a built-in polymer jacket. We prepare purified Ge-As-Se-Te glasses that are used in extruding a preform. This preform is then thermally drawn continuously in an ambient environment into extended robust infrared fibers that transmit light in the 3 ‒ 12 micron spectral range.
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.
This paper provides an up-to-date review of research efforts in thermal camera and target object recognition techniques
based on two-dimensional (2D) images in the infrared (IR) spectra (8-12μm). From the geometric point of view, a
special target plate was constructed with a radiation source of lamp excited that allows all of these devices to be
calibrated geometrically along a radiance-based approach. The calibration theory and actual experimental procedures
were described, then an automated measurement of the circle targets by image centroid algorithm. The key parameters of
IR camera were calibrated out with 3 inner and 6 outer of Tsai model in thermal imaging. The subsequent data
processing and analysis were then outlined. The 3D model from the successful calibration of a representative sample of
the infrared array camera was presented and discussed. They provide much new and easy way to the geometric
characteristics of these imagers that can be used in car-night-vision, medical, industrial, military, and environmental
At first, the paper carries on the stable state thermal analysis to the temperature field distribution of the drawing furnace,
then, a rod-in-tube technique is described here to the fabrication of tellurite glass fiber. There are some equipments
needed, which are designed according to the dimension of the fiber required. The different combinations of these
equipment could meet the various requirements, such as the rotating equipment and drawing furnace under vacuum
controlling, for the aim of fiber fabrication with high diameter ratio of cladding to core (DRCC) for single-mode optical
In optic communication field, fiber is the most adoptive material, as it is endowed with well performances in optic communication, amplifier, sensor, power delivery and so on. In this paper, species of fiber and their main applications are introduced, then, the invention and subsequent development of main methods for making optical fibers are reviewed and compared, with the ordinary vapor deposition methods of MCVD, PCVD, VAD, OVD, all kinds of casting methods, direct drawing method of two-crucibles, extruding methods to SCF and POF, special fabrication methods to optic fibers or hollow wave guides.
With the newly arisen fibers of PCF, SMNWs, there are also some descriptions about their main principles, fabrication methods and future development. In conclusion, some optimism predictions of fiber are drawn out based on the requirement of wide-band communication and optic wave-guides technology.
The new preform fabrication technique, based on the direct-melt method and modified by the hot-jointing process, for tellurite based single mode optical fibers was developed. There are only some simple moulds needed, which are designed according to the dimension of the perform required. The different combinations of these moulds could be met the various requirements, such as the preform with high diameter ratio of cladding to core (DRCC) for single-mode optical fibers. The adoption of the hot-jointing method can prevent the preform from the fragile and inner stress comparing to the direct glass machining. This technique can also be used to fabricate other oxide and low melting point glasses. The jointing process is performed at a high temperature, which results in the core and cladding boundary melted well without the bubbles. The experimental results show that the large DRCC preforms could be made by this new technique, the preforms for drawing single mode optical fibers with the DRCC of 25 were fabricated. The single mode fibers were drawn from these preforms and the upconversion luminescence of Er3+ in the fiber with the length of 70cm could be observed.