The present invention is related to a front-end circuit for an optical communication system including a laser module arranged for transmitting bursts of data signals over an optical network and a driving circuit for providing the bursts of data signals to the laser module. The front-end circuit further includes receiver means in connection with said laser module and arranged for receiving from the optical network optical echo signals. The laser module includes a laser diode arranged for transmitting the bursts of data signals. The driving circuit is arranged for setting a disabling signal for stopping the laser diode from transmitting bursts of the data signals. Fiber-related information can be extracted from the echo signals, such as distance-resolved optical fiber reflections and fiber attenuation.