Abstract:
An isotopically-altered, silica based optical fiber is provided having lower losses, broader bandwidth, and broader Raman gain spectrum characteristics than conventional silica-based fiber. A heavier, less naturally abundant isotope of silicon or oxygen is substituted for a lighter, more naturally abundant isotope to shift the infrared absorption to a slightly longer wavelength. In one embodiment, oxygen-18 is substituted for the much more naturally abundant oxygen-16 at least in the core region of the fiber. The resulting isotopically-altered fiber has a minimum loss of 0.044 dB/km less than conventional fiber, and a bandwidth that is 17 percent broader for a loss range between 0.044-0.034 dB/km. The fiber may be easily manufactured with conventional fiber manufacturing equipment by way of a plasma chemical vapor deposition technique. When a 50 percent substitution of oxygen-18 for oxygen-16 is made in the core region of the fiber, the Raman gain spectrum is substantially broadened.
Abstract translation:提供了一种同位素改性的二氧化硅基光纤,其比传统的二氧化硅基光纤具有更低的损耗,更宽的带宽和更广泛的拉曼增益光谱特性。 更重,较不自然丰富的硅或氧的同位素代替较轻的,更自然的丰富的同位素,以将红外吸收转移到稍长的波长。 在一个实施方案中,氧-18至少在纤维的核心区域中替代天然丰富的氧-16。 所得到的同位素改变的光纤比常规光纤的损耗最小为0.044 dB / km,对于0.044-0.034 dB / km之间的损耗范围,宽带宽为17%。 纤维可以通过等离子体化学气相沉积技术容易地用传统的纤维制造设备制造。 当在纤维的纤芯区域中进行氧-16取代氧-16的50%时,拉曼增益谱显着扩大。
Abstract:
Methods, apparatus and precursors for producing substantially water-free silica soot, preforms and glass. The methods and apparatus make substantially water-free fused silica preforms or glass by removing water as a reaction product, removing water from the atmosphere, removing water from the transport process, or combinations thereof. In a first embodiment, substantially water-free soot, preforms or glass are achieved by using a hydrogen-free fuel, such as carbon monoxide, in the deposition process. In another embodiment, a soot producing burner has parameters that enable operation on a substantially hydrogen-free fuel. End burners, which minimize water production, are also described. Such water-free methods are useful in depositing fluorine-doped soot because of the low water present and the efficiency in which fluorine is incorporated. In another embodiment, glassy barrier layer methods and apparatus are described for minimizing dopant migration, especially fluorine. Laser and induction methods and apparatus for forming the barrier layer are depicted. A chlorine, fluorine and silica precursor, such as chlorofluorosilane, may be utilized to form fluorinated soot. Other methods and apparatus are directed to combinations of conventional and substantially water-free processes. One embodiment is directed to combustion enhancing additives for addition to the substantially hydrogen-free fuels. The methods and apparatus in accordance with the invention are particularly useful for producing photomask substrates and optical fiber preforms.