High speed electro-optic clock recovery circuit

• US 7,130,545 B2
• Filed: 06/22/2001
• Issued: 10/31/2006
• Est. Priority Date: 06/22/2001
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Lou, Janet W., Carruthers, Thomas F.
• Primary Examiner(s): Sedighian, M. R.
• Application Number:
  US10/166,324
• Publication Number:
  US 20030058503A1
• Time in Patent Office: 1,957 Days
• Field of Search: 398/155, 398/183, 398/163, 398/192, 398/198, 388/198
• US Class Current: 398/198
• CPC Class Codes: H04L 7/0075 with photonic or optical means

Abstract

An electro-optic clock recovery circuit comprising an electro-optic modulator circuit operatively coupled to; a photodetector circuit; a buffer circuit operatively coupled to said photodetector circuit; a voltage controlled oscillator operatively coupled to said buffer circuit and to said electro-optic modulator circuit; wherein the electro-optic modulator circuit receives and modulates a multi-channel input data stream, the photodetector circuit responsive to the modulated input data stream drives the voltage controlled oscillator in a phase locked loop through the buffer circuit, and the modulator circuit is responsive to the voltage controlled oscillator and is driven at a harmonic of the voltage controlled oscillator. A method for the recovery of a single channel clock rate from a optical time division multiplexed data stream whose data rate is a multiple of the base rate comprising the steps of: modulating a multi-channel data stream with an electro-optic modulator circuit, detecting the modulated data steam with a photodetector circuit, controlling the frequency of a voltage controlled oscillator with the voltage associated with the photodetector circuit; driving the electro-optic modulator circuit with the output of the voltage controlled oscillator wherein the transmission window of the electro-optic modulator is toggled at a harmonic of the frequency of said voltage controlled oscillator.

Claims

1. An electro-optic clock recovery circuit comprising:

an electro-optic modulator circuit comprising a Mach-Zehnder modulator;

a balanced photodetector circuit operatively coupled to said modulator circuit, and comprising at least one slow photodetector series coupled to a second photodetector;

a buffer circuit;

a voltage controlled oscillator operatively coupled to said photodetector circuit through said buffer circuit; and

at least one frequency multiplier operatively coupled to said voltage controlled oscillator and said electro-optic modulator circuit,

wherein said electro-optic modulator circuit is operatively coupled to said voltage controlled oscillator circuit in a phased lock loop, receives an optical time division multiplexed data stream and samples the entire optical data stream,

wherein said voltage controlled oscillator comprises a voltage controlled oscillator frequency and wherein the at least one frequency multiplier comprises a harmonic of said voltage controlled oscillator frequency.

2. The apparatus of claim 1 wherein said balanced photodetector circuit comprises at least one slow photodetector series coupled to a second photodetector.

3. An electro-optic clock recovery circuit comprising:

an electro-optic modulator circuit comprising a Sagnac modulator operatively coupled to;

a balanced photodetector circuit, wherein said balanced photodetector circuit comprises at least one slow photodetector series coupled to a second photodetector;

a buffer circuit operatively coupled to said balanced photodetector circuit;

a voltage controlled oscillator operatively coupled to said buffer circuit and to said electro-optic modulator circuit;

at least one frequency multiplier operatively coupled to said voltage controlled oscillator and said electro-optic modulator circuit, wherein said voltage controlled oscillator comprises a voltage controlled oscillator frequency and wherein the at least one frequency multiplier comprises a harmonic of said voltage controlled oscillator frequency

wherein said electro-optic modulator circuit receives and modulates a data stream, said photodetector circuit responsive to said modulated input data stream drives said voltage controlled oscillator in a phase locked loop through said buffer circuit, and said modulator circuit is responsive to said voltage controlled oscillator and is driven at a harmonic of said voltage controlled oscillator.

4. The apparatus of claim 3 wherein said balanced photodetector circuit comprises at least one slow photodetector series coupled to a second photodetector.

5. The apparatus of claim 3 wherein said electro-optic modulator circuit samples all channels of a multi-channel data stream.

6. The apparatus of claim 3 wherein said electro-optic modulator is biased at minimum transmission.

7. The apparatus of claim 3 wherein said buffer circuit comprises an amplifier.