Method and apparatus for conditioning optical solitons

• US 6,130,767 A
• Filed: 11/13/1997
• Issued: 10/10/2000
• Est. Priority Date: 03/04/1995
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Harvey, Henry John, Hardcastle, Ian, King, Jonathan Paul
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): Singh, Dalzid
• Application Number:
  US08/913,199
• Time in Patent Office: 1,062 Days
• Field of Search: 359/181, 359/161, 359/173, 385/122
• US Class Current: 398/199
• CPC Class Codes: H04B 10/25077 using soliton propagation

Abstract

At a receiver a 20 Gbit/s soliton bit stream is demultiplexed into two 10 Gbit/s bit streams using a 2-way splitter, a clock extraction circuit, and a pair of polarization insensitive amplitude modulators exhibiting positive chirp. The outputs of the modulators are fed to detectors via lengths of optical fiber exhibiting normal dispersion thereby producing bit streams with increased mark/space ratio and reduced timing jitter.

Claims

1. A method of conditioning an optical soliton principal bit stream in which method the solitons are divided into a plurality of interleaved subsidiary bit streams using a plurality of optical amplitude modulators that impart chirp to the solitons of the subsidiary bit streams, wherein each subsidiary bit stream is launched into an associated length of optical waveguide exhibiting chromatic dispersion, and wherein the sign of the chirp imparted by the modulators is the opposite of the sign of the chromatic dispersion of the lengths of optical waveguide.

2. A method as claimed in claim 1, wherein said principal bit stream is divided into two interleaved subsidiary bit streams.

3. A method of conditioning as claimed in claim 1, wherein the modulators impart positive chirp to the solitons of the subsidiary bit streams.

4. A method as claimed in claim 3, wherein said principal bit stream is divided into two interleaved subsidiary bit streams.

5. A conditioner of optical solitons that includes a clock extraction circuit and an optical input optically coupled by means of an n-way optical power splitter (6) with a set of n amplitude modulators that exhibit chirp, wherein the clock extraction circuit has an output connected to a divide-by-n circuit (10) that is adapted to provide, for the n modulators, a set of n drives interleaved in time, each at a reciprocal-n times the clock output of the clock extraction circuit, wherein a set of n lengths of optical waveguide exhibiting chromatic dispersion are optically coupled with the n-way splitter via the n modulators, and wherein the sign of the chirp of the modulators is the opposite of the sign of the chromatic dispersion of the lengths of optical waveguide.

6. A soliton conditioner as claimed in claim 5, wherein the n-way optical power splitter is a 2-way power splitter.

7. A soliton conditioner as claimed in claim 5, wherein the modulators exhibit positive chirp.

8. A soliton conditioner as claimed in claim 7, wherein the n-way optical power splitter is a 2-way power splitter.