# US 8,787,773 B2 · Electronic dispersion correction circuit for optical transmission system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,787,773 B2 - Document ID: US8787773B2 - Status: Granted - Kind: B2 - Application number: 13/467,389 - Filed: 2012-05-09 - Published: 2013-11-14 - Granted: 2014-07-22 - Earliest claimed: 2012-05-09 - Assignees: Motorola Mobility LLC - Applicants: Jun Wang - Inventors: Jun Wang - Web page: https://patentgrep.com/patent/US8787773B2 ## CPC - H04B 10/25137: {using pulse shaping at the transmitter, e.g. pre-chirping or dispersion supported transmission [DST]} - H04B 10/25751: {Optical arrangements for CATV or video distribution (adaptations of television systems for optical transmission H04N7/22)} - H04B: TRANSMISSION ## Abstract A dispersion correction circuit is provided for use with an input driving signal. The dispersion correction circuit includes an input portion an output portion and a filter portion. The input portion is arranged to receive the input driving signal. The output portion can output an output signal based on the input driving signal. The filter portion is disposed between the input portion and the output portion. The filter portion includes a first varactor, a DC bias portion, and a second varactor. The DC bias portion provides a DC bias to the first varactor. The first varactor is arranged in a first polarity direction, and the second varactor is arranged in a second polarity direction that is the same as the first direction. ## Claims ### Claim 1 A dispersion correction circuit for use with an input driving signal, the dispersion correction circuit comprising: an input portion arranged to receive the input driving signal; an output portion operable to output an output signal based on the input driving signal; and a filter portion disposed between the input portion and the output portion, wherein the filter portion includes a first varactor, a DC bias portion, and a second varactor, wherein the DC bias portion provides a DC bias to the first varactor, wherein the first varactor is arranged in a polarity direction, and wherein the second varactor is arranged in the polarity direction, an anode of the first varactor being connected to a cathode of the second varactor. ### Claim 2 (depends on 1) The dispersion correction circuit of claim 1, wherein the DC bias portion includes a first inductor. ### Claim 3 (depends on 2) The dispersion correction circuit of claim 2, wherein the filter portion includes a third varactor arranged in parallel with one of the first varactor and the second varactor. ### Claim 4 (depends on 2) The dispersion correction circuit of claim 2, wherein the filter portion includes a second DC bias portion, a capacitor and an inductor. ### Claim 5 (depends on 1) The dispersion correction circuit of claim 1, wherein the filter portion includes a third varactor arranged in parallel with one of the first varactor and the second varactor. ### Claim 6 (depends on 5) The dispersion correction circuit of claim 5, wherein the input portion includes a second DC bias portion, a capacitor and an inductor. ### Claim 7 (depends on 1) The dispersion correction circuit of claim 1, wherein the input portion includes a second DC bias portion, a capacitor and an inductor. ### Claim 8 An optical transmission system comprising: a driver operable to provide an input signal; a dispersion correction circuit operable to generate an electrical output signal, the dispersion correction circuit including an input portion, an output portion and a filter portion; and a laser operable to output an optical signal based on the electrical output signal, wherein the input portion is arranged to receive the input signal, wherein the output portion is operable to output an output signal based on the input signal, and wherein the filter portion is disposed between the input portion and the output portion, wherein the filter portion includes a first varactor, a DC bias portion and a second varactor, wherein the DC bias portion provides a DC bias to the first varactor, wherein the first varactor is arranged in a polarity direction, and wherein the second varactor is arranged in the polarity direction, an anode of the first varactor being connected to a cathode of the second varactor. ### Claim 9 (depends on 8) The optical transmission system of claim 8, wherein the DC bias portion includes an inductor. ### Claim 10 (depends on 9) The optical transmission system of claim 9, wherein the filter portion includes a third varactor arranged in parallel with one of the first varactor and the second varactor. ### Claim 11 (depends on 9) The optical transmission system of claim 9, wherein the filter portion includes a second DC bias portion, a capacitor, and a second inductor. ### Claim 12 (depends on 8) The optical transmission system of claim 8, wherein the filter portion includes a third varactor arranged in parallel with one of the first varactor and the second varactor. ### Claim 13 (depends on 12) The optical transmission system of claim 12, wherein the input portion includes a second DC bias portion, a capacitor and an inductor. ### Claim 14 (depends on 8) The optical transmission system of claim 8, wherein the input portion includes a second DC bias portion, a capacitor and an inductor. ### Claim 15 A method of compensating for dispersion associated with an input driving signal, the method comprising: receiving, via an input portion, the input driving signal; filtering, via a filter portion, the input driving signal; outputting, via an output portion, an output signal based on the filtered input driving signal; and wherein the filter portion includes a first varactor, a DC bias portion and a second varactor, wherein the DC bias portion provides a DC bias to the first varactor, wherein the first varactor is arranged in a polarity direction, and wherein the second varactor is arranged in the polarity direction, an anode of the first varactor being connected to a cathode of the second varactor. ### Claim 16 (depends on 15) The method of claim 15, wherein the filtering, via a filter portion, the input driving signal comprises: filtering with the DC bias portion, wherein the DC bias portion includes an inductor. ### Claim 17 (depends on 16) The method of claim 16, wherein the filtering, via a filter portion, the input driving signal comprises: filtering with a third varactor arranged in parallel with one of the first varactor and the second varactor. ### Claim 18 (depends on 15) The method of claim 15, wherein the filtering, via a filtering portion, the input driving signal comprises: filtering the input driving signal via a filter portion that includes a second DC bias portion, a capacitor and an inductor. ### Claim 19 (depends on 15) The method of claim 15, wherein the filtering, via a filter portion, the input driving signal comprises: filtering with a third varactor arranged in parallel with one of the first varactor and the second varactor. ### Claim 20 (depends on 19) The method of claim 19, wherein the receiving, via an input portion, the input driving signal comprises: receiving the input driving signal via an input portion that includes a second DC bias portion, a capacitor and an inductor.