# US 11,115,126 B2 · Fiber communication systems and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,126 B2 - Document ID: US11115126B2 - Status: Granted - Kind: B2 - Application number: 16/408,285 - Filed: 2019-05-09 - Published: 2019-08-29 - Granted: 2021-09-07 - Earliest claimed: 2016-04-12 - Assignees: Cable Television Laboratories, Inc. - Applicants: Cable Television Laboratories, Inc - Inventors: Zhensheng Jia; Luis Alberto Campos; Curtis Dean Knittie; Jing Wang - Web page: https://patentgrep.com/patent/US11115126B2 ## CPC - H04B 10/504: {using direct modulation} - H04B 10/502: {LED transmitters} - H04B 10/505: {using external modulation} - H04B 10/506: {Multiwavelength transmitters} - H04B 10/532: Polarisation modulation - H04B 10/63: Homodyne {, i.e. coherent receivers where the local oscillator is locked in frequency and phase to the carrier signal} - H04B 10/64: Heterodyne {, i.e. coherent receivers where, after the opto-electronic conversion, an electrical signal at an intermediate frequency [IF] is obtained} - H04J 14/0282: {WDM tree architectures} - H04J 14/06: Polarisation multiplex systems - H04Q 11/00: Selecting arrangements for multiplex systems (multiplex systems H04J) - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream. ## Claims ### Claim 1 An optical communication network for a passive optical network (PON) system architecture, comprising: an optical hub including at least one parent seed laser source and at least one optical line terminal (OLT) configured to transmit a downstream signal of the parent seed laser source, wherein the downstream signal includes a plurality of spaced wavelength channels; an optical transport medium configured to carry the downstream signal from the optical hub; and a plurality of distributed optical network units (ONUs) operably coupled to the optical transport medium, each ONU of the plurality of distributed ONUs (i) configured to receive at least one channel of the plurality of spaced wavelength channels, and (ii) including at least one child laser source injection locked to the parent seed laser source, wherein each ONU comprises (i) an optical circulator configured to receive a linewidth of the parent laser source and inject the received linewidth into a respective child laser source of the ONU, (ii) an optical receiver configured to perform homodyne detection to detect the at least one channel received at the respective ONU. ### Claim 2 An optical communication network for a passive optical network (PON) system architecture, comprising: an optical hub including at least one parent seed laser source and at least one optical line terminal (OLT) configured to transmit a downstream signal of the parent seed laser source, wherein the downstream signal includes a plurality of spaced wavelength channels; an optical transport medium configured to carry the downstream signal from the optical hub; and a plurality of distributed optical network units (ONUs) operably coupled to the optical transport medium, each ONU of the plurality of distributed ONUs (i) configured to receive at least one channel of the plurality of spaced wavelength channels, and (ii) including at least one child laser source injection locked to the parent seed laser source, wherein each ONU comprises (i) an optical circulator configured to receive a linewidth of the parent seed laser source and inject the received linewidth into a respective child laser source of the ONU, (ii) an optical receiver configured to detect the respective at least one channel received at the ONU, and (iii) an uplink modulator configured to transmit a modulated, injection locked upstream signal from the respective child laser source to the optical hub. ### Claim 3 (depends on 2) The network of claim 2, wherein the optical receiver is configured to perform heterodyne detection. ### Claim 4 (depends on 2) The network of claim 2, wherein the optical transport medium comprises a single mode fiber configured to carry both of the downstream signal and the modulated, injection locked upstream signal. ### Claim 5 (depends on 4) The network of claim 4, wherein the PON system architecture comprises a full duplex coherent PON. ### Claim 6 (depends on 2) The network of claim 2, wherein the optical transport medium comprises a first dedicated optical fiber configured to carry the downstream signal from the optical hub to the ONU, and a second dedicated optical fiber configured to carry the modulated, injection locked upstream signal from the ONU to the optical hub. ### Claim 7 (depends on 2) The network of claim 2, wherein the child laser source comprises a Fabry-Perot (FP) laser. ### Claim 8 (depends on 7) The network of claim 7, wherein the at least one parent seed laser source comprises an external cavity laser (ECL). ### Claim 9 (depends on 8) The network of claim 8, where the optical hub further comprises an optical comb generator having an input configured to receive an output beam of the ECL laser, and an output configured to generate the plurality of spaced wavelength channels for transport to the OLT. ### Claim 10 (depends on 2) The network of claim 2, further comprising at least 500 ONUs communicatively coupled with a single OLT at the optical hub. ### Claim 11 (depends on 10) The network of claim 10, wherein the PON system architecture comprises a point to multipoint (P2MP) configuration. ### Claim 12 (depends on 11) The network of claim 11, wherein the optical hub is further configured to communicatively couple with a plurality of optical source fibers from a remote distributed access system. ### Claim 13 (depends on 12) The network of claim 12, wherein the plurality of optical source fibers each comprise an individual respective point to point (P2P) to link. ### Claim 14 (depends on 13) The network of claim 13, wherein the single OLT further comprises at least one secondary laser source (i) injection locked to a linewidth and frequency of the at least one parent seed laser source, and (ii) in operable communication with a respective optical source fiber of the individual respective P2P to link. ### Claim 15 A coherent optical transceiver in operable communication with an optical transport medium of an optical communication network, the coherent optical transceiver comprising: an optical circulator configured to receive a downstream coherent signal from the optical transport medium, the downstream coherent signal including a plurality of spaced wavelength channels from an upstream transmission source; a child laser source in operable communication with the optical circulator and configured for injection locking to a linewidth of a parent seed laser of the upstream transmission source; an optical receiver in operable communication with the optical circulator and configured to detect the at least one channel of the plurality of spaced wavelength channels; and an uplink modulator configured to transmit a modulated, injection locked upstream signal from the child laser source onto the optical transport medium. ### Claim 16 (depends on 15) The coherent optical transceiver of claim 15, wherein the optical communication network comprises a passive optical network (PON) system architecture. ### Claim 17 (depends on 15) The coherent optical transceiver of claim 15, wherein the optical receiver is further configured to perform homodyne detection. ### Claim 18 (depends on 15) The coherent optical transceiver of claim 15, wherein the optical receiver is further configured to perform heterodyne detection. ### Claim 19 (depends on 15) The coherent optical transceiver of claim 15, comprising an optical network unit (ONU). ### Claim 20 (depends on 15) The coherent optical transceiver of claim 15, wherein the child laser source comprises a Fabry-Perot (FP) laser.