Patent ID: 7590351
Filing Date: 2009-09-15
Classification: H04B,H04J

Abstract:
1. A method for an optical transmitter to automatically control an extinction ratio of an optical signal, the method comprising the following: an act of generating an electrical signal that is to be converted into an optical signal, the electrical signal having a plurality of power levels including a high power level and a low power level; an act of generating an electrical tone having a relatively narrow frequency spectrum; an act of using a frequency spreading circuit to frequency spread the electrical tone; an act of modulating one of the plurality of power levels of the electrical signal using the frequency spread electrical tone; an act of converting the modulated electrical signal into an optical signal using an electro-optic transducer; an act of monitoring the optical signal using an optoelectronic transducer to recover at least a distorted version of the modulated electrical signal; an act of recovering at least a distorted version of the frequency spread tone from the recovered modulated electrical signal; an act of demodulating the frequency spread tone; and an act of using the demodulated tone to control an extinction ratio for the optical signal.