LASER-BASED DEVICE UTILIZING MULTIPLE LASER BEAMS

• US 20170207856A1
• Filed: 01/17/2016
• Published: 07/20/2017
• Est. Priority Date: 01/17/2016
• Status: Active Grant

• Current Assignee: Vocalzoom Systems Ltd.
• Original Assignee: Vocalzoom Systems Ltd.
• Inventors: Fishman, Tal, Bakish, Tal, Blumkin, Alexander, Ganani, Amir
• Granted Patent: US 9,756,431 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 10/503 Laser transmitters
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/564 Power control
• CPC Class Codes: H04R 23/008 using optical signals for detecting or generating sound
• CPC Class Codes: H04R 23/02 Transducers using more than one principle simultaneously

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) optical feedback of the first laser transmitter, and (ii) optical feedback of the second laser transmitter. Alternatively, a single monitor photodiode is used, receiving optical signals from multiple laser transmitters, and outputting a single electric signal to a single laser receiver.

Claims

1. An apparatus 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 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) optical feedback of the first laser transmitter, and (ii) optical feedback of the second laser transmitter.

2. The apparatus of claim 1, wherein the first monitor photodiode is separate from the second monitor photodiode;

and wherein the first and second monitor photodiodes, and the first and second laser transmitters, and the single laser receiver, are co-located within a same packaging.

3. The apparatus of claim 1, wherein said electric connection, that connects together the first and second electric signal, is an electric connection located externally to the single laser receiver and prior to an entry node of the single laser receiver.

4. The apparatus of claim 1, wherein the first monitor photodiode and the second monitor photodiode are shorted together at a node located between (I) the first and second monitor photodiodes, and (II) an input of said single laser receiver.

5. The apparatus of claim 1, wherein said electric connection, that connects together the first and second electric signal, is an electric connection located internally within said single laser receiver.

6. The apparatus of claim 1, wherein said electric connection, that connects together the first and second electric signal, is an electric connection located at an entry node of said single laser receiver.

7. The apparatus 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, separate, laser modulator 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.

8. The apparatus 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.

9. The apparatus 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 the first laser transmitter has physical diameter of a first value;

wherein the second laser transmitter has physical diameter of a second, greater, value;

wherein, based on the different physical diameters of the first and second laser transmitters, said first and second laser transmitters transmit respectively a first laser beam and a second laser beam having two different self-mix carrier frequencies.

10. The apparatus 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 the first laser transmitter operates at a first temperature;

wherein the second laser transmitter operates at a second, greater, temperature;

wherein, based on different operational temperatures of the first and second laser transmitters, said first and second laser transmitters transmit respectively a first laser beam and a second laser beam having two different self-mix carrier frequencies.

11. The apparatus of claim 1, further comprising:

a selective activation module to selectively activate and de-activate at least one of the first laser transmitter and the second laser transmitter.

12. The apparatus of claim 1, further comprising:

a selective activation module to selectively de-activate one laser transmitter out of the first laser transmitter and the second laser transmitter, based on self-mix usefulness of optical feedback received by each one of said first and second laser transmitters.

13. The apparatus of claim 1, further comprising:

a laser usefulness estimator to estimate self-mix usefulness of optical feedback received by the first laser transmitter;

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 pre-defined threshold value.

14. The apparatus of claim 1, further comprising:

a laser usefulness estimator (i) to estimate self-mix usefulness of optical feedback received by the first laser transmitter, and (ii) to estimate self-mix usefulness of optical feedback received by the second laser transmitter;

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 smaller by at least a pre-defined ratio from an estimated self-mix usefulness value of the second laser transmitter.

15. The apparatus of claim 1, further comprising:

a laser usefulness estimator to estimate self-mix usefulness of optical feedback received by the first laser transmitter;

a selective activation module (a) to selectively reduce a level of power provided to the first laser transmitter, while maintaining the first laser transmitter activated, and (b) to maintain a level of power provided to the second laser transmitter, if an estimated self-mix usefulness value of the first laser transmitter is below a pre-defined threshold value.

16. The apparatus of claim 1, further comprising:

a laser usefulness estimator (i) to estimate self-mix usefulness of optical feedback received by the first laser transmitter, and (ii) to estimate self-mix usefulness of optical feedback received by the second laser transmitter;

a selective activation module (a) to selectively reduce a level of power provided to the first laser transmitter, while maintaining the first laser transmitter activated, and (b) to maintain a level of power provided to the second laser transmitter, if an estimated self-mix usefulness value of the first laser transmitter is smaller by at least a pre-defined ratio from an estimated self-mix usefulness value of the second laser transmitter.

17. The apparatus of claim 1, further comprising:

a selective activation module to selective de-activate one laser transmitter out of the first laser transmitter and the second laser transmitter, and to reduce power consumption of the apparatus, based on usefulness of optical feedback of the first laser transmitter relative to usefulness of optical feedback of the second laser transmitter.

18. The apparatus of claim 1, further comprising:

a selective activation module to selective de-activate one laser transmitter out of the first laser transmitter and the second laser transmitter, and to increase a Signal to Noise Ratio (SNR) of the apparatus, based on usefulness of optical feedback of the first laser transmitter relative to usefulness of optical feedback of the second laser transmitter.

19. The apparatus of claim 1, further comprising:

a single lens assembly that is common to both the first laser transmitter and the second laser transmitter.

20. The apparatus 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.

21. The apparatus 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 is located at a first distance from said single lens assembly;

wherein the first laser transmitter is located at a second, different, distance from said single lens assembly.

22. The apparatus 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.

23. The apparatus 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 drift of at least one of said first peak and said second peak in response to vibration of a remote speaker that is hit by at least one;

a laser beam transmitted by the first laser transmitter, and a laser beam transmitted by the second laser transmitter.

24. The apparatus of claim 23, wherein the spectral analysis module is to determine one or more characteristics of vibrations of said remote speaker, based on said drift monitored in said spectrum.

25. The apparatus of claim 1, wherein the apparatus comprises a laser-based microphone.

26. The apparatus of claim 1, wherein the apparatus comprises a laser-based microphone able to remotely sense vibrations of a facial-area of a human speaker while said apparatus is not in physical contact with human speaker.

27. The apparatus of claim 1, wherein the apparatus comprises a laser-based microphone able to remotely sense vibrations of a facial-area of a human speaker while said apparatus is not in physical contact with human speaker;

wherein the apparatus is embedded within a vehicular component of a vehicle in which said human speaker is located.

28. The apparatus of claim 1, wherein the apparatus comprises a hybrid acoustic-and-optical sensor which includes at least:

a laser-based microphone able to remotely sense vibrations of a facial-area of a human speaker while said apparatus is not in physical contact with human speaker;

an acoustic microphone able to capture acoustic signals generated by said human speaker.

29. The apparatus of claim 1, wherein the apparatus comprises a hybrid acoustic-and-optical sensor which includes at least:

a laser-based microphone able to remotely sense vibrations of a facial-area of a human speaker while said apparatus is not in physical contact with human speaker; and

an acoustic microphone able to capture acoustic signals generated by said human speaker;

wherein the apparatus further comprises a processor to enhance the acoustic signals, that are captured by said acoustic microphone, based on vibrations of the facial-area of the human speaker that are sensed remotely by the laser-based microphone.

30. The apparatus of claim 1, further comprising:

a third laser transmitter having a third self-mix carrier frequency, wherein the third self-mix carrier frequency is different from the first self-mix carrier frequency, wherein the third self-mix carrier frequency is different from the second self-mix carrier frequency;

a third monitor photodiode to receive a third optical signal from the third laser transmitter, and to output a third electric signal;

wherein said electric connection is to connect together the first electric signal and the second electric signal and the third electric signal;

wherein said single laser receiver is to receive an electric signal which is a combination of the first and the second and the third electric signals, and to generate from said electric signal a spectrum that corresponds to (i) optical feedback of the first laser transmitter, and (ii) optical feedback of the second laser transmitter, and (iii) optical feedback of the third laser transmitter.

31. The apparatus of claim 1, comprising:

a plurality of laser transmitters that are co-located and co-packaged, and are associated with a respective plurality of separate monitor photodiodes;

wherein each one of the laser transmitters has a self-mix carrier frequency that is different from any other self-mix carrier frequency of any other laser transmitter of the apparatus;

wherein each one of the laser transmitters provides an optical signal to each one of the respective separate monitor photodiodes;

wherein outputs of said plurality of monitor photodiodes, are connected together prior to an entry node of said single receiver.

32. The apparatus of claim 1, wherein the electric connection that connects together the first electric signal and the second electric signal, and forms the combined electric signal, is an electric connection located after the entry node of said single laser receiver, and wherein each of the first and second electric signals is pre-amplified before reaching said electric connection.

33. The apparatus 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.