New primary coating method for optical fibres

A new primary coating method for optical fibres has been developed. A locally heated and softened thermoplastic tube, in which the fibre is passing through, is drawn to form a coating layer on the fibre. This method has large advantages in forming a precisely concentric coating layer and fabricating a strong fibre.     

Transmission loss of UV-curable silicone-coated optical fibre

Transmission characteristics of UV-curable silicone-coated optical fibre were investigated in relation to the elastic property and the chemical structure of the coating. It was found that added loss of the coated fibre is less than ±0.06 dB/km in the range ?75 to 80°C. The infra-red loss increase of the UV-curable silicone-coated fibre was appreciably lower than that for thermally cured silicone-coated fibre at elevated temperatures.     

New mode scrambler for optical fibre measurements

A new design of a mode scrambler for optical fibre measurements is presented. A rotation-splice technique has been used to mix the incoming mode power distribution in the fibre. The device is tested under different launch conditions to check its efficiency to produce a definite mode power distribution. Experimental results are presented.     

New silica-based low-loss optical fibre

A new type of silica-based optical fibre has been made from relatively cheap and abundant materials. The attenuation is very low over the entire range from the near ultraviolet to the gallium-arsenide-laser wavelength. The minimum loss of 2.7 dB/km occurs at 0.83 ?m.     

New optical fibre fabrication method

A new method for optical fibre fabrication has been found. The method is based on the so-called `sol-gel process?, which enables one to produce a core rod for optical fibre. Pure silica core fibre fabricated using this method exhibits an optical attenuation characteristic as low as 6 dB/km at a wavelength of 0.85 ?m.     

New single-mode single-polarisation optical fibre

The theory for understanding fibres composed of `highly? birefringent material is presented. One of the two possible polarisation states of the fundamental mode can be made leaky, suggesting a novel single-mode single-polarisation fibre design. No leakage occurs in planar waveguides constructed similarly from the identical material.     

Electric field sensitive optical fibre using piezoelectric polymer coating

Optical fibres coated with piezoelectric polymers are shown to be sensitive conductorless detectors of electric fields. The phase shift of a fibre coated with a polymer containing PVF2 was found to be 2.3 × 10?5 radians per V/m of electric field per metre of fibre.     

光纤二次套塑用固相缩聚PBT材料

用固相缩聚方法制得的聚对苯二甲酸丁二醇酯（PBT）材料具有优良的机械性能，电性能，耐热性能和加工性能等，同时抗水解性也有很大提高，因此此材料成为国内外公认的光纤二次套塑材料。     

光纤涂层固化控制技术

讨论了在光纤生产过程中，影响光纤涂层紫外固化度的几个重要因素，并着重指出了紫外固化炉结构的改进对光纤涂层固化度的影响。     

Single-mode optical fibre microbending loss in a loose tube coating

45 km of single-mode fibre of differing detailed design has been loose-tube packaged under identical conditions. The spectral loss between 1.1 and 1.75 ?m was measured before and after packaging. The incremental loss thus deduced, and related to equivalent core size and ?n, provided information about fibre design for safe packaging.     

Modified silicone as new type of primary coat for optical fibre

It is confirmed that modified silicone is the most suitable for the primary coat of optical fibre. The modified silicone-coated fibre with a silicone buffer and a nylon jacket is found to have high mechanical strength and stable transmission characteristics.     

New polarisation-insensitive detection technique for coherent optical fibre heterodyne communications

A new technique for overcoming polarisation-induced fading in coherent optical fibre communications is described. The technique generates two IFs, which fade in antiphase, by mixing the signal light with orthogonally polarised local oscillator modes which have been separated in the frequency domain.     

New method for measuring V-value of a single-mode optical fibre

A simple method is proposed for the direct measurement of the V-value for a single-mode optical fibre. This method consists of measurement of loss peaks, corresponding to cutoff wavelengths of the higher modes, which are easily observed for a fibre with a bend.     

New fabrication technique for high performance polarisationmaintaining optical fibre couplers

A simple and novel technique for fabricating polarisation maintaining optical fibre couplers is reported. This technique is different from existing approaches of polarisation coupler fabrication, in that it avoids the need to align the polarisation axis during each coupler fabrication. Both low loss and low polarisation crosstalk have been achieved     

New method of fault detection in optical fibre links

The detection of the signal backscattered by the faults present in an optical fibre is achieved by observing the amplified signal coming out by the rear facet of the exciting laser source. This provides a simple method which employs the same semiconductor laser as a source and an amplifier, thus notably simplifying the procedure for fault detection. Some experimental results are presented.     

离子束辅助沉积薄膜工艺

阐述了离子源在离子束清洗和离子束辅助薄膜沉积（IAD）中的应用;根据热力学原理及离子碰撞过程分析,研究了离子束辅助沉积过程中的能量传递过程,建立了薄膜折射率与离子辅助沉积过程中各物理量之间的关系模型;探讨了各种工艺条件对离子束辅助沉积薄膜特性的影响,给出了薄膜材料无结晶条件下离子束辅助沉积薄膜工艺选择的相应准则。     

Noise figure for erbium-doped optical fibre amplifiers

A rate equation model is used to calculate the excess noise figure for erbium-doped fibre amplifiers. It is shown that erbium amplifiers can operate with high gain and can have noise figures only 0.2 dB above the quantum limit     

Straight-tip optical fibre up-tapers for single-mode hardwareapplications

Reports a practical optical fibre up-taper unitary structure consisting of a fibre pigtail followed by a short up-taper followed by a uniform cylindrical section (straight tip). This self-aligning ×5 beam expansion element exhibits an insertion loss of <0.1 dB and allows for simple mechanical mounting and beam alignment     

High-strength small reinforcement for spliced optical fibre

A high-strength small reinforcement using a nylon and a steel wire has been developed. The size of the reinforcement is 1 mm in diameter and 35 mm in length. An average tensile strength of 5.4 kg has been achieved with negligible loss increase.     

High-strength carbon-coated optical fibre

A carbon-coated fibre with 6.2 kgf failure strength and an n value of 670 is obtained for the first time. The carbon surface roughness was evaluated from STM images and a flat carbon coating was found to be essential in preventing the initial strength degradation of the fibre.<>