US 6,643,040 B2Granted

Optical signal converter from RZ format to NRZ format

AssigneeAlcatel

InventorsAlexandre Shen, Fabrice Devaux

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Abstract

The present invention is a device for converting an RZ signal into a NRZ signal which contains an optical bistable device (5), where an output level of this device passing from a low level to a high level when an input power level crosses in an upward direction a first threshold, and returning to a low level when an input level crosses in a downward direction a second threshold below the first, the output (7) of the bistable (5) carrying the NRZ signal, and a device (2) for converting the RZ signal into a control signal of an output logic level of the optical bistable device (5) receiving the RZ signal, and delivering the control signal of the optical bistable device (5), this signal having a level above the first threshold when the RZ signal passes to 1 and which becomes lower at the second threshold only if the RZ signal passes to 0 and stays there for more than one bit time.

Claims10

Dependent claims

A device for converting a binary digital optical signal in the RZ format having a bit time into a binary digital optical signal in the NRZ format characterized in that it comprises:

an optical bistable means having an input and an output, an output logic level of this optical bistable means passing from a low level to a high level when a power level present at input passes from a level below a first threshold S1 to a level above this first threshold S1 and passing from a high level to a low level when the power level present at input passes from a level above a second threshold to a level below this second threshold, the second threshold being below the first threshold, the output of this optical bistable means carrying the NRZ format signal;
a means for converting the binary digital optical signal in the RZ format into a control signal of an output logic level of the optical bistable means, this conversion means having an input and an output, this means receiving, at its input, the RZ signal to be converted and delivering at its output said control signal, said output being coupled to the input of the optical bistable means, the conversion means producing a signal the level of which becomes above the first threshold when a signal present at the input of this circuit passes from a low logic level present for more than one bit time to a high logic level and remains at a level above the second threshold so long as the input signal does not return for more than one bit time to a low logic level, and producing a signal having a level below the second threshold when a signal present at the input of this means passes from a high logic level to a low logic level and remains there for more than one bit time.

A wholly optical process of converting an RZ signal carried by an optical carrier wave having a first wavelength into an optical NRZ signal, characterized in that the process comprises:

outputting a logic level from an optical bistable means, wherein said output passes from a low logic level to a high logic level when an input power is above a first threshold S1 and passes back to a low logic level when the input power goes back down to a level below a second threshold S2 below the first threshold,
converting the RZ signal to be converted into a control signal of the bistable means, wherein the control signal passes from a value below the first threshold to a value above the first threshold each time that the RZ signal passes from a low logic level present for more than one bit time to a high logic value, and to a value below the second threshold if the RZ signal to be converted passes from a high logic level to a low logic level and remains there for more than one bit time of the RZ signal, and
applying the control signal to the bistable device to obtain at the output from the bistable circuit the NRZ signal carrying the same information as the RZ signal to be converted.

A device for converting a binary digital optical signal in the RZ format having a bit time into a binary digital optical signal in the NRZ format characterized in that it comprises:

an optical bistable means having an input and an output, an output logic amplitude of this optical bistable means passing from a low amplitude to a high amplitude when a power amplitude present at input passes from an amplitude below a first threshold S1 to an amplitude above this first threshold S1 and passing from a high amplitude to a low amplitude when the power amplitude present at input passes from an amplitude above a second threshold to an amplitude below this second threshold, the second threshold being below the first threshold, the output of this optical bistable means carrying the NRZ format signal;
a means for converting the binary digital optical signal in the RZ format into a control signal of an output logic amplitude of the optical bistable means, this conversion means having an input and an output, this means receiving, at its input, the RZ signal to be converted and delivering at its output said control signal, said output being coupled to the input of the optical bistable means, the conversion means producing a signal the amplitude of which becomes above the first threshold when a signal present at the input of this circuit passes from a low logic amplitude present for more than one bit time to a high logic amplitude and remains at an amplitude above the second threshold so long as the input signal does not return for more than one bit time to a low logic amplitude, and producing a signal having a amplitude below the second threshold when a signal present at the input of this means passes from a high logic amplitude to a low logic amplitude and remains there for more than one bit time.

Dependencies are inferred from the claim text.

Facts

Application: 09/961,311Filed 25 Sep 2001
Priority: FR 00 127285 Oct 2000
Published: US 2002/0041408 A111 Apr 2002
Granted: 4 Nov 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04B 10/299
In which processing or amplification is carried out without conversion of the main signal from optical form: signal waveform processing, e.g.…
G02F 3/022
Optical bistable devices: based on electro-, magneto- or acousto-optical elements
H04B 2210/517
Indexing scheme relating to optical transmission systems: optical NRZ to RZ conversion, or vice versa
H04B
Transmission