摘要 |
An electronic telephone exchange of the type employing time-space-time switching, has an optical fiber data link connecting the space and time switches. In order to meet the design requirements for use in a telephone exchange, the fiber optic link has to have fairly well defined performance parameters. In particular the overall diameter of the optical fibers employed in the optical fiber link lies between 180 and 250 microns, preferably 200 microns, and the core diameter of the optical fibers lies in the range 0.6 to 0.95 of the cladding diameter. Preferably the core diameter lies in the range 160-180 microns. The optical fiber link is characterized by the numerical aperture of the fiber, insertion loss of the fiber, sensitivity and dynamic range of detector, and the power output and extinction ratio of the transmitter. |