# US 2018/0027339 A1 · Laser-Based Devices Utilizing Multiple Laser Beams > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0027339 A1 - Document ID: US20180027339A1 - Status: Published application - Kind: A1 - Application number: 15/679,168 - Filed: 2017-08-17 - Published: 2018-01-25 - Earliest claimed: 2016-01-17 - Applicants: VocalZoom Systems Ltd. - Inventors: Alexander Blumkin; Amir Ganani; Tal Fishman; Tal Bakish - Web page: https://patentgrep.com/patent/US20180027339A1 ## CPC - H04R 23/008: {using optical signals for detecting or generating sound} - H04B 10/503: {Laser transmitters} - H04B 10/506: {Multiwavelength transmitters} - H04B 10/564: Power control - H04R 23/02: Transducers using more than one principle simultaneously - H04R 2410/00: Microphones - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - H04B: TRANSMISSION ## Abstract A laser-based device or sensor includes: a first laser transmitter having a first self-mix carrier frequency; a second laser transmitter having a second, different, self-mix carrier frequency; a first monitor photodiode to receive a first optical signal from the first laser transmitter, and to output a first electric signal; a second monitor photodiode to receive a first optical signal from the second laser transmitter, and to output a second electric signal; an electric connection to connect together the first electric signal and the second electric signal, forming a combined electric signal; a single laser receiver to receive the combined electric signal and to generate from it a spectrum that corresponds to both (i) self-mix signal of the first laser transmitter, and (ii) self-mix signal of the second laser transmitter. Alternatively, a single monitor photodiode is used, receiving self-mix signals from multiple laser transmitters, and outputting a single electric signal to a single laser receiver. ## Claims ### Claim 1 A device comprising: a first laser transmitter having a first self-mix carrier frequency; a second laser transmitter having a second, different, self-mix carrier frequency; a single monitor photodiode (A) to receive a first optical signal from the first laser transmitter, (B) to receive a second optical signal from the second laser transmitter, (C) to output a single electric signal that corresponds to both the first optical signal and the second optical signal; a single laser receiver to receive the single electric signal and to generate from it a spectrum that corresponds to both (i) self-mix signal of the first laser transmitter, and (ii) self-mix signal of the second laser transmitter. ### Claim 2 (depends on 1) The device of claim 1, comprising a plurality of laser transmitters that are co-located and co-packaged, wherein all of said laser transmitters are associated with said single monitor photodiode that is external to and separate from all said laser transmitters and is internal to said device. ### Claim 3 (depends on 1) The device of claim 1, further comprising: a first laser modulator to modulate the first laser transmitter at a first waveform, and to cause the first laser transmitter to transmit a first laser beam having the first self-mix carrier; a second laser modulator that is separate from the first laser modulator, wherein the second laser modulator is to modulate the second laser transmitter at a second waveform, and to cause the second laser transmitter to transmit a second laser beam having the second self-mix carrier. ### Claim 4 (depends on 1) The device of claim 1, wherein the first laser transmitter has a first delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the first laser transmitter as a function of a change in current supplied to said first laser transmitter; wherein the second laser transmitter has a second delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the second laser transmitter as a function of a change in current supplied to said second laser transmitter; wherein the first delta-wavelength to delta-current value of the first laser transmitter is identical to the second delta-wavelength to delta-current value of the second laser transmitter. ### Claim 5 (depends on 1) The device of claim 1, wherein the first laser transmitter has a first delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the first laser transmitter as a function of a change in current supplied to said first laser transmitter; wherein the second laser transmitter has a second delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the second laser transmitter as a function of a change in current supplied to said second laser transmitter; wherein the first delta-wavelength to delta-current value of the first laser transmitter is non-identical to the second delta-wavelength to delta-current value of the second laser transmitter. ### Claim 6 (depends on 1) The device of claim 1, wherein the first laser transmitter has a first delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the first laser transmitter as a function of a change in current supplied to said first laser transmitter; wherein the second laser transmitter has a second delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the second laser transmitter as a function of a change in current supplied to said second laser transmitter; wherein the first delta-wavelength to delta-current value of the first laser transmitter is non-identical to the second delta-wavelength to delta-current value of the second laser transmitter; wherein the ratio between (I) the first delta-wavelength to delta-current value of the first laser transmitter and (II) the second delta-wavelength to delta-current value of the second laser transmitter, is not greater than 1.05 and is not smaller than 0.95. ### Claim 7 (depends on 1) The device of claim 1, wherein the first laser transmitter has a first delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the first laser transmitter as a function of a change in current supplied to said first laser transmitter; wherein the second laser transmitter has a second delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the second laser transmitter as a function of a change in current supplied to said second laser transmitter; wherein the first delta-wavelength to delta-current value of the first laser transmitter is non-identical to the second delta-wavelength to delta-current value of the second laser transmitter; wherein the ratio between (I) the first delta-wavelength to delta-current value of the first laser transmitter and (II) the second delta-wavelength to delta-current value of the second laser transmitter, is not greater than 1.10 and is not smaller than 0.90. ### Claim 8 (depends on 1) The device of claim 1, wherein the first laser transmitter has a first delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the first laser transmitter as a function of a change in current supplied to said first laser transmitter; wherein the second laser transmitter has a second delta-wavelength to delta-current value, which indicates a change in wavelength of a laser beam that is transmitted by the second laser transmitter as a function of a change in current supplied to said second laser transmitter; wherein the first delta-wavelength to delta-current value of the first laser transmitter is non-identical to the second delta-wavelength to delta-current value of the second laser transmitter; wherein the ratio between (I) the first delta-wavelength to delta-current value of the first laser transmitter and (II) the second delta-wavelength to delta-current value of the second laser transmitter, is not greater than 1.20 and is not smaller than 0.80. ### Claim 9 (depends on 1) The device of claim 1, further comprising: a spectral analysis module configured (A) to analyze a spectrum of signals received by said single laser receiver, and (B) to identify in said spectrum a first peak and a second peak that correspond, respectively, to the first laser transmitter and the second laser transmitter, and (C) to monitor a frequency shift of at least one of said first peak and said second peak in response to movement of a remote target that is hit by at least one of: a laser beam transmitted by the first laser transmitter, and a laser beam transmitted by the second laser transmitter, and (D) to determine one or more characteristics of said remote target, based on said drift monitored in said spectrum. ### Claim 10 (depends on 1) The device of claim 1, wherein the single monitor photodiode is separate from both the first laser transmitter and the second laser transmitter. ### Claim 11 (depends on 1) The device of claim 1, wherein the first and second laser transmitters are co-packaged; and wherein the single monitor photodiode is integrated within the co-packaged first and second laser transmitters. ### Claim 12 (depends on 1) The device of claim 1, wherein the first and second laser transmitters are monolithically integrated with each other; and wherein the single monitor photodiode is also monolithically integrated within the first and second laser transmitters. ### Claim 13 (depends on 1) The device of claim 1, wherein the first and second laser transmitters are monolithically integrated with each other; and wherein the single monitor photodiode is not monolithically integrated within the first and second laser transmitters. ### Claim 14 (depends on 1) The device of claim 1, further comprising: a single laser modulator connected to both the first laser transmitter and the second laser transmitter; wherein said single laser modulator utilizes a first electric circuitry to modulate the first laser transmitter at a first waveform, and to cause the first laser transmitter to transmit a first laser beam having the first self-mix carrier; wherein said single laser modulator utilizes a second electric circuitry to modulate the second laser transmitter at a second waveform, and to cause the second laser transmitter to transmit a second laser beam having the second self-mix carrier. ### Claim 15 (depends on 1) The device of claim 1, further comprising: a single laser modulator connected to both the first laser transmitter and the second laser transmitter; wherein said single laser modulator provides a same modulation to both the first laser transmitter and the second laser transmitter; wherein, by utilizing a Distributed Bragg Reflector (DBR) doping technique, said first and second laser transmitters transmit respectively a first laser beam and a second laser beam having two different self-mix carrier frequencies. ### Claim 16 (depends on 1) The device of claim 1, further comprising: a laser usefulness estimator, to estimate self-mix signal usefulness of the first laser transmitter, by comparing a quality indicator of the self-mix signal usefulness of the first laser transmitter to one or more pre-defined threshold values; a selective activation module (a) to selectively de-activate the first laser transmitter and (b) to maintain the second laser transmitter activated, if an estimated self-mix usefulness value of the first laser transmitter is below a particular pre-defined threshold value. ### Claim 17 (depends on 1) The device of claim 1, further comprising: a laser usefulness estimator, to estimate self-mix signal usefulness of the first laser transmitter, by comparing a Root Mean Square (RMS) amplitude of the self-mix signal of the first laser transmitter to one or more pre-defined threshold values; a selective activation module (a) to selectively de-activate the first laser transmitter and (b) to maintain the second laser transmitter activated, if an estimated self-mix usefulness value of the first laser transmitter is below a particular pre-defined threshold value. ### Claim 18 (depends on 1) The device of claim 1, further comprising: a single lens assembly that is common to both the first laser transmitter and the second laser transmitter; wherein the first laser transmitter and the second laser transmitter are located at a same distance from said single lens assembly.