Abstract: A connector endpiece for interconnecting two optical fibers end-to-end, the endpiece comprising a cylindrical body (1) provided with an axial bore (2) for receiving the end of one of the optical fibers to be connected (5), and having a polished plane front face for fixing in one half of the bore of a hollow connection sleeve (13) face-against-face with an identical connector endpiece housing the end of the other optical fiber (5A), the endpiece being characterized in that it further comprises a short optical element (7) of material having the same refractive index as that of the optical fibers to be interconnected, having a plane rear face (9) and having a front face presenting excellent surface state (8; 11), said element being disposed in the front portion of the bore of the endpiece in such a manner that the rear face of the element is close to the front end (6) of the corresponding optical fiber, and the front end of the element is flush with the polished plane front face (3) of the endpiece, a thin layer

Abstract: The receiver of an optical-fiber transmission system comprises a device for restoring each digital signal comprising a first comparator comparing the level of the electric signal with a first reference level and generating a signal when the level of the electric signal is less than the reference level, a second comparator comparing the level of the electric signal with a second reference level and generating a signal when the level of the electric signal is greater than the reference level, and a summator summing the signals generated by the two comparators.

Abstract: An alarm-triggering device for the receiver of an optical-fiber transmission system including in series a filter which has a passband located externally with respect to the band of frequencies employed for optical-fiber transmission and the input of which is connected to an avalanche photodiode, an amplifier, a rectifier, a voltage comparator circuit, and alarm-triggering circuit.