摘要:
A spherical lens formed by fusing a generally homogenous glass lens blank to the distal end of an optical fiber, heating and tensioning the lens blank to separate it in two segments with the segment attached to the optical fiber defining a tapered end, and heating the lens blank above its softening point so that the spherical lens forms. The lens blank is fabricated from a 4 weight percent borosilicate glass having a softening point less than that of the core of the optical fiber. The lens member defines a throat region adjacent the optical fiber whose cross-sectional dimension is substantially greater than the diameter of the optical fiber, but substantially less than the diameter of the spherical lens.
摘要:
Methods and apparatus for detecting air/cladding and core/cladding interfaces of blanks (13) used to produce optical waveguide fibers are provided. A beam of coherent light (30) is scanning across the blank (13) and spatial light intensity patterns produced thereby (FIG. 5) are detected and analyzed. Air/cladding interfaces correspond to a decrease in the width of a unimodal spatial light intensity pattern as the beam moves towards the center of the blank (FIGS. 5A and 5B). Core/cladding interfaces correspond to the onset of an at least bimodal spatial light intensity pattern as the beam moves towards the center of the blank (FIGS. 5D and 5E). By rotating the blank and repeating the measurement process at two or more angular positions, concentricity and ellipticity values for a blank can be determined.
摘要:
Apparatus for interconnecting two or more high gain, low input impedance amplifier stages for high gain amplification. A first amplifier stage (12) provides a first amplified signal to a coupling circuit. The coupling circuit (26) divides the power of the first amplified signal between the input to a second amplifier stage (14) and a feed forward path (28). The output of the second amplifier stage is combined with the feed forward portion of the first amplified signal in a signal combiner (30). Embodiments (FIGS. 4, 5) employing more than two amplifier stages are described.