Acousto-optic modulators for modulating light signals

• US 20080225376A1
• Filed: 07/26/2007
• Published: 09/18/2008
• Est. Priority Date: 09/22/2003
• Status: Active Grant

• Current Assignee: Hyeung-Yun Kim
• Original Assignee: Hyeung-Yun Kim
• Inventors: Kim, Hyeung-Yun
• Granted Patent: US 7,729,035 B2
• Time in Patent Office: Days
• US Class Current: 359/287
• CPC Class Codes: G01H 11/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties
• CPC Class Codes: G01H 11/08 using piezoelectric devices
• CPC Class Codes: G01H 9/004 using fibre optic sensors light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125
• CPC Class Codes: G01M 11/086 Details about the embedment of the optical fiber within the DUT
• CPC Class Codes: G01M 11/088 of optical fibres; Mechanical features associated with the optical testing of optical fibres
• CPC Class Codes: G01M 5/0016 of aircraft wings or blades
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 29/043 in the interior, e.g. by shear waves
• CPC Class Codes: G01N 29/245 Ceramic probes, e.g. lead zirconate titanate [PZT] probes
• CPC Class Codes: G01N 29/2475 Embedded probes, i.e. probes incorporated in objects to be inspected
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00

Abstract

Devices for modulating light signals. A modulator includes a rolled optical fiber cable having a preset tensile stress along the longitudinal axis thereof, a coating layer applied to the rolled optical cable, and at least one piezo acoustic transducer secured to the coating layer. The piezo acoustic transducer is operative to generate a sound wave that modulates a frequency of a light signal passing through the rolled optical fiber cable.

Claims

1. A modulator for modulating a light signal, comprising:

a rolled optical fiber cable having a preset tensile stress along a longitudinal axis thereof;

a coating layer applied to the rolled optical cable; and

at least one piezo acoustic transducer secured to the coating layer and operative to generate a sound wave that modulates a frequency of a light signal passing through the rolled optical fiber cable.

2. A modulator as recited in claim 1, wherein the piezo acoustic transducer includes:

a first piezo acoustic transducer secured to a top surface of the coating layer and having a piezo disk and a first pair of conductive flakes disposed on top and bottom surfaces thereof;

a second piezo acoustic transducer secured to a bottom surface of the coating layer and having a piezo disk and a second pair of conductive flakes disposed on top and bottom surfaces thereof; and

electrical wires for transmitting electric signals to the first and second pairs of conductive flakes.

3. A modulator as recited in claim 2, further comprising:

a signal generator coupled to the electrical wires.

4. A modulator as recited in claim 3, wherein the signal generator is a radio frequency signal generator.

5. A modulator as recited in claim 2, wherein the modulator has a generally ring shape.

6. A modulator as recited in claim 2, wherein the modulator has a generally circular disk shape

7. A modulator as recited in claim 1, wherein the piezo acoustic transducer includes:

a piezo ceramic cylinder having a cylindrical surface on which the rolled optical cable and coating layer are disposed;

a pair of conductive flakes respectively disposed on top and bottom surfaces of the piezo ceramic cylinder; and

a pair of electrical wires transmitting electrical signals to the pair of conductive flakes.

8. A modulator as recited in claim 7, further comprising:

a signal generator coupled to the pair of electrical wires.

9. A modulator as recited in claim 8, wherein the signal generator is a radio frequency signal generator.

10. A modulator as recited in claim 1, wherein the coating layer is formed of material selected from the group consisting of epoxy, polyimide, silicon-polyimide, piezoelectric ceramic polymer, aluminum, copper, gold, silver, zinc oxide, silicon oxide, tantalum oxide, silica, silicon carbide, tungsten carbide, silicon nitride, and graphite.

11. A modulator as recited in claim 1, wherein the coating layer is formed of adhesive material.

12. A modulator as recited in claim 1, wherein the rolled optical fiber cable includes a single-mode polyimide-coated fiber.

13. A modulator as recited in claim 1, wherein the rolled optical fiber cable includes a multi-mode polyimide-coated fiber.

14. A modulator as recited in claim 1, wherein the rolled optical fiber cable is coated with material selected from the group consisting of aluminum, copper, gold, and silica.

15. A device for multiple wavelength modulation, comprising:

a stack of modulation units, each said modulation unit including;

a rolled optical fiber cable having a preset tensile stress along a longitudinal axis thereof;

a coating layer applied to the rolled optical cable;

a first piezo acoustic transducer secured to a top surface of the coating layer and having a piezo disk and a first pair of conductive flakes disposed on top and bottom surfaces thereof;

a second piezo acoustic transducer secured to a bottom surface of the coating layer and having a piezo disk and a second pair of conductive flakes disposed on top and bottom surfaces thereof; and

electrical wires for transmitting electrical signals to the first and second pairs of conductive flakes,

wherein the first and second piezo acoustic transducers are operative to generate a sound wave that modulates a frequency of a light signal passing through the rolled optical fiber cable.

16. A modulator as recited in claim 15, wherein the modulator has a generally ring shape.

17. A modulator as recited in claim 15, wherein the modulator has a generally circular disk shape.

18. A modulator as recited in claim 15, further comprising:

a signal generator coupled to the electrical wires of the modulation units.

19. A modulator as recited in claim 18, wherein the signal generator is a radio frequency signal generator.

20. A modulator as recited in claim 15, further comprising:

a plurality of signal generators, each said signal generator being coupled to electrical wires of a corresponding modulation unit.

21. A modulator as recited in claim 20, wherein each of the signal generators is a radio frequency signal generator.