Tellabs Operations, Inc.

North American Philips Corporation

Eric J Frankfort

Paul C Talmadge

John C Carrick

Roger P Holmstrom

Stuart D Brorson

Robert McFarlane

George C Kenney

Methods and apparatus for maintaining a pre-determined ratio of a pilot tone power and a total mean optical power of an optical signal are provided. One apparatus includes an optical source coupled to provide an optical signal in response to a DC bias and an AC bias corresponding to a pilot tone signal. A processor is coupled to compute each of an AC component and a DC component of the optical signal from the same digitally sampled signal. A feedback control is coupled to vary at least one of the DC bias and the AC bias in accordance with a difference between a pre-determined value and a ratio of the AC and DC components.

Method and apparatus for maintaining a pre-determined ratio of a pilot tone power and a mean optical output power of an optical signal

Methods and apparatus related to maintaining a pre-determined ratio of a pilot tone power and a total mean optical power of an optical signal are provided. One method includes the steps of detecting the AC and DC components of an optical signal having a pilot tone signal. An amplitude of the pilot tone signal is varied in accordance with a difference between a pre-determined value and a ratio of the AC and DC components. Another method includes the step of generating an optical signal in accordance with a DC bias and an AC bias corresponding to a pilot tone signal. The AC and DC components of the optical signal are detected. At least one of the DC bias and the AC bias is varied in accordance with a difference between a pre-determined value and a ratio of the AC and DC components. An apparatus includes an optical source providing an optical signal in response to a DC bias and an AC bias corresponding to a pilot tone signal. The apparatus includes detectors coupled to measure the AC and DC components of the optical signal. A feedback control varies at least one of the DC bias and the AC bias in accordance with a difference between a pre-determined value and a ratio of the AC and DC components. In various embodiments, the DC bias only, the AC bias only, or both the AC bias and the DC bias are varied.

Apparatus for recording data by means of a beam of radiation on a recording medium which upon exposure to the beam undergoes optically detectable changes in the form of pits, which apparatus includes means for reducing the beam intensity as a result of pit initiation thereby forming more accurate pits.

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Yorktown Heights, NY, United States of America

Eric J Frankfort