Transducer for converting acoustic energy directly into optical energy

• US 4,071,753 A
• Filed: 03/31/1975
• Issued: 01/31/1978
• Est. Priority Date: 03/31/1975
• Status: Expired due to Term

• Current Assignee: GTE Laboratories Incorporated (Lumen Technologies, Inc.)
• Original Assignee: GTE Laboratories Incorporated (Lumen Technologies, Inc.)
• Inventors: Fulenwider, John E., Gonsalves, John
• Primary Examiner(s): La Roche, Eugene R.
• Application Number:
  US05/563,869
• Time in Patent Office: 1,037 Days
• Field of Search: 250/227, 250/231 R, 250/231 P, 250/233, 250/199, 250/234, 350/96 R, 350/96 C
• US Class Current: 250/227.21
• CPC Class Codes: G01H 9/006 the vibrations causing a variation in the relative position of the end of a fibre and another element
• CPC Class Codes: G01L 1/243 using means for applying force perpendicular to the fibre axis
• CPC Class Codes: G01L 11/025 using a pressure-sensitive optical fibre
• CPC Class Codes: G01L 9/0076 using photoelectric means
• CPC Class Codes: G01L 9/0077 for measuring reflected light
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 6/3502 involving direct waveguide displacement, e.g. cantilever type waveguide displacement involving waveguide bending, or displacing an interposed waveguide between stationary waveguides
• CPC Class Codes: G02B 6/3514 the reflective optical element moving along a line so as to translate into and out of the beam path, i.e. across the beam path
• CPC Class Codes: G02B 6/352 the reflective optical element having a shaped reflective surface, e.g. a reflective element comprising several reflective surfaces or facets that function together
• CPC Class Codes: G02B 6/3552 1x1 switch, e.g. on/off switch
• CPC Class Codes: G02B 6/3574 Mechanical force, e.g. pressure variations
• CPC Class Codes: G02B 6/3594 Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams

Abstract

A transducer is disclosed in which energy received from either mechanical or acoustic sources is converted into modulated optical power. The transducer is comprised of three basic components, an input optical fiber, an output optical fiber and a means for varying the optical coupling coefficient between the two fibers in response to information containing energy received from a mechanical or acoustic source. The input optical fiber carries a steady state optical signal which may be either continuous or pulsed. The means operates to control the coupling of the steady state optical signal into the output optical fiber. An intensity modulated output signal is then carried by the output optical fiber away from the transducer. The intensity modulated output signal may be either detected and thereby converted to electrical energy for transmission or may be transmitted in an optical form if optical communications facilities are available.

Claims

1. A transducer for converting acoustic energy directly into optical energy without first converting the energy into electrical form comprising:

an input optical fiber for carrying steady state optical power and having an output end;

a source of steady state optical power connected to the input optical fiber;

an output optical fiber for carrying modulated optical power and having an input end, the input end being normally optically positioned relative to the output end of the input fiber so that a predetermined portion of the optical power carried by the input optical fiber is coupled into the output optical fiber;

a diaphragm for receiving acoustic information containing energy from a source and for producing at an output an oscillatory mechanical motion indicative of the acoustic information;

means responsive to the mechanical output of the diaphragm for varying the portion of optical power coupled between the input optical fiber and the output optical fiber; and

a transducer housing to which the output end of the input optical fiber, the input end of the output optical fiber, the diaphragm and the means for varying the portion of coupled optical power are physically connected for support and protection,

the means for varying the coupled optical power including the respective end of one of the optical fibers being fixedly positioned within the transducer housing and the respective end of the other of the optical fibers being connected to the diaphragm so that upon impingement of information containing acoustic energy against the diaphragm relative oscillatory lateral movement is established between the respective ends of the optical fibers to cause a variance in the optical power coupled into the output optical fiber thereby providing amplitude modulation of the optical power carried by the output optical fiber.

2. A transducer for converting acoustic energy directly into optical energy without first converting the energy into electrical form comprising:

a transducer housing;

an input optical fiber for carrying steady state optical power and having an output end fixedly positioned to the housing;

a source of steady state optical power connected to the input optical fiber;

an output optical fiber for carrying modulated optical power and having an input end fixedly positioned to the housing in juxtaposed relation with the output end of the input fiber to form a gap therebetween, the input end being normally optically positioned relative to the output end of the input fiber so that a predetermined portion of the optical power carried by the input optical fiber is coupled into the output optical fiber;

a diaphragm for receiving acoustic information containing energy from a source and for producing at an output an oscillatory mechanical motion indicative of the acoustic information; and

means connected to the diaphragm and extending into the gap between the respective ends thereby interrupting at least a portion of the optical power emitted from the output end of the input optical fiber so that upon impingement of acoustic energy against the diaphragm lateral movement of the means is established to cause a variance in the optical power coupled into the output optical fiber thereby providing modulation of the optical power carried by the output optical fiber.

3. An optical transducer according to claim 2, wherein the means connected to the diaphragm is a birefringent wedge.

4. An optical transducer according to claim 2, wherein the means connected to the diaphragm is an opaque member.

5. A transducer for converting acoustic energy directly into optical energy without first converting the energy into electrical form comprising:

an input optical fiber for carrying steady state optical power and having an output end;

a source of steady state optical power connected to the input optical fiber;

an output optical fiber for carrying modulated optical power and having an input end, the input end being normally optically positioned relative to the output end of the input fiber so that a predetermined portion of the optical power carried by the input optical fiber is coupled into the output optical fiber;

a diaphragm for receiving acoustic information containing energy from a source and for producing at an output an oscillatory mechanical motion indicative of the acoustic information;

means responsive to the mechanical output of the diaphragm for varying the portion of optical power coupled between the input optical fiber and the output optical fiber;

a transducer housing to which the output end of the input optical fiber, the input end of the output optical fiber, the diaphragm and the means for varying the portion of coupled optical power are physically connected for support and protection,

the optical fibers being aligned parallel to each other with the respective ends essentially coplanar and pointed in the same direction; and

a porro prism pivoted at its apex and having a transmitting face parallel to the plane of the ends of the optical fibers, the prism being pivoted at its apex about a line parallel to the plane and approximately midway between the optical fibers, the porro prism being connected to the diaphragm so that upon impingement of energy against the diaphragm rocking of the prism about the line occurs causing a variance in the optical power reflected into the output optical fiber thereby producing modulation of the optical power carried by the output optical fiber.