A method of measuring the stresses, residual or applied, in an optical fiber or preform is presented. It is shown that the stress profiles can be obtained from the Abel transform of the derivative of the retardation. The axial stress profile is shown to bear the same shape as the refractive-index profile. Measurement results indicate that the applied tension during the fiber drawing process is frozen into the fiber, consequently affecting the intrinsic strength of the fiber. The method of estimating the fiber drawing tension from the fiber stress profile is also given.

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A modified focusing method for measuring simultaneously the refractive-index profile and the cross-sectional geometry of an optical fiber preform is presented. In this method the preform is immersed in indexmatching liquid, and collimated light is made to impinge on the preform laterally. The intensity distributions of the transmitted light are detected on two planes inside the preform core. From the recorded light intensity distributions, the deflection function is calculated. After the preform has been rotated through 180 degrees and the necessary data have been collected, a numerical inversion is performed to obtain the 2-D index profile. In this paper, the principle, the experimental setup, and results are described. The sensitivity of the method to measurement errors and the accuracy of the inversion formula were investigated by computer simulations. It was found that the error of the index profile measurement was <1%.

The historical, clinical and histopathological features of three dogs with eosinophilic folliculitis and furunculosis are described. The disease was characterised by the rapid development of pruritic, papular, pustular and ulcerative lesions on the dorsum of the muzzle. Skin lesions were confined to the face in two cases. The third dog had more generalised pustular lesions. Skin biopsy specimens showed marked eosinophil infiltration particularly centred on pilosebaceous units. Dermal collagen necrosis was evident in two cases. Similar facial lesions have previously been described as 'nasal pyoderma'. The three dogs failed to respond to initial antibacterial therapy but showed a rapid clinical response when prednisolone was given orally at doses ranging from 1 to 2.2 mg/kg, in addition to the antibacterial therapy, suggesting that glucocorticoids are indicated for the treatment of eosinophilic folliculitis and furunculosis. The aetiology of the disease was not determined.