Patent ID: 6509994
Filing Date: 2003-01-21
Classification: H04B

Abstract:
An optical transmitter for receiving electrical signals and for providing optical signals in a communications network, the optical transmitter comprising:an analog-to-digital (A/D) converter coupled to an input of the optical transmitter for converting the electrical signals to digital signals; a delay circuit coupled to the A/D converter for delaying the digital signals; a digital-to-analog (D/A) converter coupled to the delay circuit for converting the digital signals back to analog signals; a digital carrier-detect circuit coupled to the A/D converter for detecting the presence of digital signals, which are representative of the input electrical signals; a switch responsive to the carrier-detect circuit; and a laser coupled to the D/A converter for converting the analog signals into the optical signals; wherein the digital carrier-detect circuit closes the switch when detecting the presence of digital signals and opens the switch in the absence of digital signals, whereby the optical transmitter transmits optical signals only when presented with electrical signals at the input.