Abstract: A digital logic interface circuit makes use of a logic signal representative of a logic signaling level definition, to determine the logic swing amplitude of signals from a given source adopting the same logic signaling level definition. The digital logic interface circuit generates a threshold level from the logic swing amplitude thus determined, and compares digital logic input signals against the threshold level in order to discriminate different logic levels in the digital logic input signals. The comparison result is provided as digital interface output signals adopting a predetermined logic signaling level definition for use by subsequent system sections. Examples of such representative signals are the digital input logic signals themselves, clock signals or line encoded signals. Other examples can be mode control signals or NRZ signals.

Abstract: An integrated device is provided having both laser and modulator sections. The laser section generates a primary light signal using a distributed feedback process. The modulator section influences the primary light signal by means of an electroabsorption process. The laser and modulator sections are electrically separated from each other with respect to anode and cathode areas. As a result, a single supply voltage can be used to operate the device. An optical transmitter contains, in addition to the integrated device, a protocol converter which receives an information signal to be transmitted and generates a control signal which is received by a modulator driver. Based thereon, the modulator driver produces a modulating signal, which causes a modulated light signal representing the information signal to be output. A laser bias control unit controls the output power level of the primary light signal based on a leak signal from the laser section.