Abstract: In aligning ends of optical fibers, e.g. for performing a prealignment of ends of large mode area double-clad fibers (LMA-DCFs) in order to thereafter perform a core alignment process, in a fiber optic fusion splicer a best, optimum or near optimum position or setting of the optical system for observing the self-focusing effect is first determined and then the very alignment operation may be performed using the determined setting. The very alignment process may then be performed by adjusting stepwise the offset distance between the observed fiber ends by e.g. using a cascade technique.

Abstract: In aligning ends of optical fibers, e.g. ends of large mode area double-clad fibers (LMA-DCFs), in a fiber optic fusion splicer the best position of the object plane of the optical system for observing images of the cores of the fiber ends are first determined by maximizing the contrast of the core image, in particular the core image peak in intensity profiles. The alignment process may be performed by adjusting the offset distance between the observed cores in some suitable way, e.g. by using a cascade technique. In e.g. a process for prealigning the fiber ends the self-focusing effect of optical fibers can be used to first determine the best object plane position for observing the self-focusing effect and then the very pre-alignment operation can be performed. This may extend the range of image analysis allowing e.g. that alignment, in particular core alignment, can be performed without requiring direct information showing the position of sides or edges of the claddings in captured pictures.

Abstract: In aligning ends of optical fibers, e.g. for performing a prealignment of ends of large mode area double-clad fibers (LMA-DCFs) in order to thereafter perform a core alignment process, in a fiber optic fusion splicer a best, optimum or near optimum position or setting of the optical system for observing the self-focusing effect is first determined and then the very alignment operation may be performed using the determined setting. The very alignment process may then be performed by adjusting stepwise the offset distance between the observed fiber ends by e.g. using a cascade technique.

Abstract: In aligning ends of optical fibers (13), e.g. for performing a prealignment of ends of large mode area double-clad fibers (LMA-DCFs) in order to thereafter perform a core alignment process, in a fiber optic fusion splicer a best, optimum or near optimum position or setting of the optical system (7) for observing the self-focusing effect is first determined and then the very alignment operation may be performed using the determined setting. The very alignment process may then be performed by adjusting stepwise the offset distance between the observed fiber ends by e.g. using a cascade technique.

Abstract: In aligning ends of optical fibers, e.g. ends of large mode area double-clad fibers (LMA-DCFs), in a fiber optic fusion splicer the best position of the object plane of the optical system for observing images of the cores of the fiber ends are first determined by maximizing the contrast of the core image, in particular the core image peak in intensity profiles. The alignment process may be performed by adjusting the offset distance between the observed cores in some suitable way, e.g. by using a cascade technique. In e.g. a process for prealigning the fiber ends the self-focusing effect of optical fibers can be used to first determine the best object plane position for observing the self-focusing effect and then the very pre-alignment operation can be performed. This may extend the range of image analysis allowing e.g. that alignment, in particular core alignment, can be performed without requiring direct information showing the position of sides or edges of the claddings in captured pictures.

Abstract: In positioning or aligning ends of optical fibers in relation to each other an offset distance between the fiber ends, the offset distance e.g. being the distance between predetermined reference positions in the fiber ends, is stepwise adjusted using a cascade technique. The method can be executed accurately and fast and be used e.g. in a procedure for core alignment, the predetermined reference positions then being the positions of the cores of the fiber ends such as the positions of the center lines or axes of the cores. Also, the method can be used in a procedure in which the self-focusing effect of optical fibers is used for finding the reference positions, which in this case are the positions of the center lines or axes of the total fiber ends, i.e. center lines or axes of the surfaces of the claddings of the optical fiber ends. Finally, the method can be used for the longitudinal positioning of the fiber ends in which the gap between end surfaces of the fiber ends is set to a desired value.

Abstract: In positioning or aligning ends of optical fibers in relation to each other an offset distance between the fiber ends, the offset distance e.g. being the distance between predetermined reference positions in the fiber ends, is stepwise adjusted using a cascade technique. The method can be executed accurately and fast and be used e.g. in a procedure for core alignment, the predetermined reference positions then being the positions of the cores of the fiber ends such as the positions of the center lines or axes of the cores. Also, the method can be used in a procedure in which the self-focusing effect of optical fibers is used for finding the reference positions, which in this case are the positions of the center lines or axes of the total fiber ends, i.e. center lines or axes of the surfaces of the claddings of the optical fiber ends. Finally, the method can be used for the longitudinal positioning of the fiber ends in which the gap between end surfaces of the fiber ends is set to a desired value.

Abstract: In aligning ends of optical fibers (13), e.g. for performing a prealignment of ends of large mode area double-clad fibers (LMA-DCFs) in order to thereafter perform a core alignment process, in a fiber optic fusion splicer a best, optimum or near optimum position or setting of the optical system (7) for observing the self-focusing effect is first determined and then the very alignment operation may be performed using the determined setting. The very alignment process may then be performed by adjusting stepwise the offset distance between the observed fiber ends by e.g. using a cascade technique.

Abstract: The present invention relates to a method for accurately calibrating fusion temperature in optical fiber splicing. With assistance of direct arc-recentering technique, two optical fibers are spliced and then continuously heated with a post-fusion process. In the process, the fusion temperature is automatically determined in terms of effective fusion currents, which is done by real-time monitoring the fusion time dependence of cladding diameter reduction. In comparison with model calculations, variations of fusion temperature caused by changes of electrode condition and operating environment, e.g. altitude, temperature and humidity are derived. To recover the optimal fusion temperature in various fusion processes, the calibrating results are automatically invoked to compensate fusion currents.