• unknown: optical fiber
• unknown: tellurite glass
• unknown: insertion loss
• unknown: thermal expansion coefficient
• unknown: optical fiber
• unknown: tellurite glass
• unknown: insertion loss
• unknown: thermal expansion coefficient
• unknown: optical fiber
• unknown: tellurite glass
• unknown: insertion loss
• unknown: thermal expansion coefficient

Several nano liters of tellurite glass melt
(xTeO2-(100-x)ZnO, x=80,90,100 in mol%)
were inserted and quenched between two ends of silica glass optical
fibers to form a new optical coupling structure, whose length was
several hundred microns. No visible precipitates were found even in the
quenched melt of 100% TeO2. On the basis of reflection and
insertion loss measurements and a bending test, it is proved that
there's no micro crystals in the quenched melt segment which cause light
scattering and/or stress concentration.

Few tens nano liters of the melt were also inserted into a silica glass
capillary tube with the interior diameter of 126 $\mu$m, in order to
examine their tolerance to the residual stress induced on cooling due to
the large gap in thermal expansion coefficient between the two glasses.
Neither fracture nor bubbles were observed in the quenched melt inside
if its length is less than 2mm. This implies that tellurite melt can be
introduced into voids of sub-mm in size to integrate hybrid lightwave
circuits.