# US 12,009,912 B2 · WDM channel reassignment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,912 B2 - Document ID: US12009912B2 - Status: Granted - Kind: B2 - Application number: 17/888,947 - Filed: 2022-08-16 - Published: 2023-09-28 - Granted: 2024-06-11 - Earliest claimed: 2022-03-23 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Company, Ltd. - Inventors: Chih-Chang Lin; Chan-Hong Chern; Stefan Rusu; Weiwei Song; Lan-Chou Cho - Web page: https://patentgrep.com/patent/US12009912B2 ## CPC - H04B 10/505: {using external modulation} - H04J 14/0283: {WDM ring architectures} - G02F 1/0147: {based on thermo-optic effects (G02F1/132 takes precedence)} - H04B 10/506: {Multiwavelength transmitters} - H04J 14/0221: {Power control, e.g. to keep the total optical power constant} - G02F 2203/15: involving resonance effects, e.g. resonantly enhanced interaction - 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) - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract An optical device includes a first waveguide, ring-shaped waveguides adjacent to the first waveguide, and heaters coupled to the ring-shaped waveguides in one-to-one correspondence. A method includes coupling a first light source with a first wavelength to the first waveguide, increasing electric current through the heaters until a first one of the ring-shaped waveguides resonates, assigning the first one of the ring-shaped waveguides to the first wavelength, resetting the electric current through the heaters to the initial electric current, coupling a second light source with a second wavelength to the first waveguide wherein the second wavelength is different from the first wavelength, increasing the electric current through the heaters until a second one of the ring-shaped waveguides resonates wherein the second one of the ring-shaped waveguides is different from the first one of the ring-shaped waveguides, and assigning the second one of the ring-shaped waveguides to the second wavelength. ## Claims ### Claim 1 A method for operating an optical device, wherein the optical device includes a first waveguide, multiple ring-shaped waveguides adjacent to the first waveguide, and multiple heaters coupled to the ring-shaped waveguides in one-to-one correspondence, wherein each of the multiple heaters is supplied with an initial electric current, the method comprising: coupling a first light source with a first wavelength to the first waveguide; increasing electric current through the heaters until a first one of the ring-shaped waveguides resonates, wherein the first one of the ring-shaped waveguides is coupled to a first one of the heaters; assigning the first one of the ring-shaped waveguides to the first wavelength; resetting the electric current through the heaters or the heaters excluding the first one of the heaters to the initial electric current; coupling a second light source with a second wavelength to the first waveguide, wherein the second wavelength is different from the first wavelength; increasing the electric current through the heaters or the heaters excluding the first one of the heaters until a second one of the ring-shaped waveguides resonates, wherein the second one of the ring-shaped waveguides is different from the first one of the ring-shaped waveguides; and assigning the second one of the ring-shaped waveguides to the second wavelength. ### Claim 2 (depends on 1) The method of claim 1, wherein the initial electric current is substantially zero amperes. ### Claim 3 (depends on 1) The method of claim 1, wherein the optical device includes multiple heater control loops that are configured to control the multiple heaters in one-to-one correspondence, further comprising: before the coupling of the first light source, disabling the heater control loops; and after the assigning of the first one of the ring-shaped waveguides to the first wavelength, enabling one of the heater control loops that corresponds to the first one of the heaters. ### Claim 4 (depends on 1) The method of claim 1, wherein the multiple ring-shaped waveguides include four or more ring-shaped waveguides. ### Claim 5 (depends on 1) The method of claim 1, wherein the optical device includes an optical transmitter and each of the ring-shaped waveguides is a part of a micro-ring modulator. ### Claim 6 (depends on 5) The method of claim 5, after the assigning of the second one of the ring-shaped waveguides to the second wavelength, further comprising: modulating the first wavelength by applying a first electric signal to the first one of the ring-shaped waveguides, thereby generating a modulated first light signal; modulating the second wavelength by applying a second electric signal to the second one of the ring-shaped waveguides, thereby generating a modulated second light signal; and multiplexing the modulated first light signal and the modulated second light signal into a transmitting light signal. ### Claim 7 (depends on 1) The method of claim 1, wherein the optical device includes an optical receiver and each of the ring-shaped waveguides is a part of a ring resonator. ### Claim 8 (depends on 7) The method of claim 7, after the assigning of the second one of the ring-shaped waveguides to the second wavelength, further comprising: receiving a light signal having a first component at the first wavelength and a second component at the second wavelength; coupling the light signal to the multiple ring-shaped waveguides; and demultiplexing the light signal to a first light signal through the first one of the ring-shaped waveguides and a second light signal through the second one of the ring-shaped waveguides. ### Claim 9 A method for operating an optical transmitter, wherein the optical transmitter includes a first waveguide, multiple micro-ring modulators (MRMs) adjacent to the first waveguide, and multiple heaters coupled to the MRMs in one-to-one correspondence, wherein each of the multiple heaters is supplied with an initial electric current, the method comprising the steps of: coupling a light source with a wavelength to the first waveguide; increasing electric current through each of the heaters until one of the MRMs resonates, wherein the one of the MRMs is coupled to one of the heaters; assigning the one of the MRMs to the wavelength; resetting the electric current through the heaters or the heaters excluding the one of the heaters to the initial electric current; and repeating the steps of coupling, increasing, assigning, and resetting until each of the MRMs is assigned to a different wavelength. ### Claim 10 (depends on 9) The method of claim 9, before the step of coupling, further comprising: turning off an automatic heater control loop to each of the multiple heaters. ### Claim 11 (depends on 9) The method of claim 9, wherein the MRMs include a multiple of four MRMs. ### Claim 12 (depends on 9) The method of claim 9, further comprising: biasing each of the MRMs to a fixed biasing voltage during the steps of coupling, increasing, assigning, resetting, and repeating. ### Claim 13 (depends on 9) The method of claim 9, further comprising: applying a toggling electric signal to each of the MRMs during the steps of coupling, increasing, assigning, resetting, and repeating. ### Claim 14 (depends on 9) The method of claim 9, further comprising: storing values of electric current through each of the heaters that cause the respective MRMs to resonate during the step of increasing electric current. ### Claim 15 (depends on 9) The method of claim 9, wherein the steps of coupling, increasing, assigning, resetting, and repeating are performed during an initialization procedure of the optical transmitter. ### Claim 16 A system comprising: an optical transmitter, wherein the optical transmitter includes a first waveguide, multiple micro-ring modulators (MRMs) disposed adjacent to the first waveguide, and multiple heaters coupled to the MRMs in one-to-one correspondence; multiple heater controllers coupled to the multiple heaters in one-to-one correspondence; and an assignment controller that is configured to perform: coupling a light source to the first waveguide; instructing the heater controllers to increase electric current through the heaters until one of the MRMs resonates, wherein the one of the MRMs is coupled to one of the heaters; and assigning the one of the MRMs to a wavelength of the light source. ### Claim 17 (depends on 16) The system of claim 16, wherein the assignment controller is further configured to perform: resetting the electric current through the heaters or the heaters excluding the one of the heaters to an initial electric current; and repeating the steps of coupling, instructing, and resetting until each of the MRMs is assigned to a different wavelength. ### Claim 18 (depends on 17) The system of claim 17, wherein the assignment controller is further configured to perform: storing results of assigning the MRMs to the different wavelengths. ### Claim 19 (depends on 16) The system of claim 16, wherein the optical transmitter further includes multiple ring modulator drivers (RMDs) that are coupled to the MRMs in one-to-one correspondence. ### Claim 20 (depends on 16) The system of claim 16, wherein the optical transmitter further includes multiple photo detectors, and each of the photo detectors is coupled between one of the MRMs and a corresponding one of the heater controllers.