# US 9,438,007 B2 · Optical modulator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,007 B2 - Document ID: US9438007B2 - Status: Granted - Kind: B2 - Application number: 14/740,241 - Filed: 2015-06-15 - Published: 2016-01-07 - Granted: 2016-09-06 - Earliest claimed: 2013-03-14 - Assignees: Emcore Corporation - Applicants: EMCORE Corporation - Inventors: Henry A. Blauvelt; Xiaoguang He; Kerry Vahala - Web page: https://patentgrep.com/patent/US9438007B2 ## CPC - H01S 5/0265: {Intensity modulators (intra-cavity modulators H01S5/0625)} - H01S 5/0085: {for modulating the output, i.e. the laser beam is modulated outside the laser cavity} - H01S 5/026: Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06) - H01S 5/1092: {Multi-wavelength lasing} - H04B 10/2575: Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier - H04B 10/25759: {Details of the reception of RF signal or the optical conversion before the optical fibre} - H04B 10/505: {using external modulation} - H04B 10/54: Intensity modulation - H04B 10/588: in external modulation systems - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - H04B: TRANSMISSION ## Abstract An optical modulator including an information-containing radio frequency signal input; a semiconductor device having an optical input optically for receiving the coherent light beam, and a electrode connected to said radio frequency signal input and having a modulated bias potential so that current is generated in the second semiconductor device and extracted therefrom, while the coherent light beam is optically modulated by the signal changing the carrier density in the semiconductor device. ## Claims ### Claim 1 A method for operating an optical modulator that includes a modulator optical waveguide formed on a substrate, the method comprising: (a) launching an continuous-wave input optical signal to propagate along the modulator optical waveguide, the input optical signal being characterized by an input optical power level; and (b) applying an electrical modulation signal to a modulator electrode positioned over a semiconductor modulator active region of the modulator optical waveguide so as to modulate an optical transmission level of the input optical signal through the modulator resulting in a modulated output optical signal emitted from the modulator, wherein: (c) the optical modulator is characterized by a zero-current modulator optical transmission level that is less than 100% and occurs at a positive modulator bias voltage level that results in charge carriers being neither injected into nor extracted from the modulator active region; (d) an electrical modulation signal level that causes charge carriers to be injected into the modulator active region results in a modulator optical transmission level higher than the zero-current modulator transmission level; and (e) an electrical modulation signal level that causes charge carriers to be extracted from the modulator active region results in a modulator optical transmission level lower than the zero-current modulator transmission level. ### Claim 2 (depends on 1) The method of claim 1 wherein the zero-current modulator optical transmission level is dependent on the input optical power level. ### Claim 3 (depends on 1) The method of claim 1 wherein the electrical modulation signal comprises a sum of a substantially constant positive modulator bias voltage and an information-carrying RF modulation signal applied to the modulator electrode. ### Claim 4 (depends on 3) The method of claim 3 wherein the modulator bias voltage is greater than about 0.4 V. ### Claim 5 (depends on 3) The method of claim 3 wherein applying the modulator bias voltage and the RF modulation signal results in charge carriers being extracted from the modulator active region over a portion of a negative-current region of an I-V characteristic of the modulator active region. ### Claim 6 (depends on 5) The method of claim 5 wherein the charge carriers extracted from the modulator active region result in a negative current from about 0 mA to about 50 mA. ### Claim 7 (depends on 1) The method of claim 1 further comprising generating the continuous-wave input optical signal from a semiconductor laser by applying a substantially constant electrical laser bias voltage to a laser electrode positioned over a semiconductor laser active region of a laser optical waveguide formed on the substrate, wherein the laser and modulator waveguides are arranged so that at least a portion of optical output of the semiconductor laser is launched to propagate as the input optical signal along the modulator optical waveguide. ### Claim 8 (depends on 7) The method of claim 7 wherein the laser and modulator electrodes are electrically separated by a vertical gap formed in semiconductor material between the electrodes. ### Claim 9 (depends on 7) The method of claim 7 wherein the laser and modulator optical waveguides are distinct portions of a common optical waveguide formed on the substrate. ### Claim 10 (depends on 7) The method of claim 7 wherein the laser bias voltage is greater than the modulator bias voltage. ### Claim 11 (depends on 7) The method of claim 7 wherein the semiconductor laser includes InP. ### Claim 12 (depends on 7) The method of claim 7 wherein the laser optical waveguide includes a reflective first end region and a second end region adjacent the modulator optical waveguide. ### Claim 13 (depends on 7) The method of claim 7 wherein the input optical signal is characterized by a wavelength of about 1550 nm. ### Claim 14 (depends on 1) The method of claim 1 wherein the optical modulator includes InP. ### Claim 15 (depends on 1) The method of claim 1 wherein the input optical signal is characterized by a wavelength of about 1550 nm.