In-fiber variable optical attenuators and modulators using index-changing liquid media

• US 6,621,952 B1
• Filed: 08/10/2001
• Issued: 09/16/2003
• Est. Priority Date: 08/10/2000
• Status: Expired due to Fees

• Current Assignee: Intelligent Fiber Optic Systems Corporation
• Original Assignee: Oluma, Inc. (Intelligent Fiber Optic Systems, Inc.)
• Inventors: Pi, Bo, Zhao, Shulai
• Primary Examiner(s): Ullah, Akm Enayet
• Assistant Examiner(s): Doan, Jennifer
• Application Number:
  US09/927,105
• Time in Patent Office: 767 Days
• Field of Search: 385/15, 385/16, 385/28, 385/30, 385/31, 385/32, 385/39, 385/140
• US Class Current: 385/30
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/12019 characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes coupling integrated waveguide to fibre G02B6/30, to optoelectronic element G02B6/42; monolithic integration of integrated waveguides with other optical elements G02B6/12004
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/2804 forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
• CPC Class Codes: G02B 6/2826 using mechanical machining means for shaping of the couplers, e.g. grinding or polishing grinding, polishing in general B24
• CPC Class Codes: G02B 6/2852 using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
• CPC Class Codes: G02B 6/29355 Cascade arrangement of interferometers
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/351 involving stationary waveguides with moving interposed optical elements G02B6/3538 takes precedence; interposed waveguides G02B6/3502
• CPC Class Codes: G02B 6/3536 involving evanescent coupling variation, e.g. by a moving element such as a membrane which changes the effective refractive index mode converters G02B6/14; adjustable lateral coupling between waveguides G02B6/283; electro- optical refractive index variations G02F1/0118
• CPC Class Codes: G02B 6/3538 based on displacement or deformation of a liquid controlling the intensity of light by displacement or deformation of a fluid in general G02B26/004; fluid-filled lens of variable focal length G02B3/14
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3636 the mechanical coupling means being grooves G02B6/3652 takes precedence
• CPC Class Codes: G02B 6/3652 the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers
• CPC Class Codes: G02B 6/3692 with surface micromachining involving etching, e.g. wet or dry etching steps surface micromachining involving subtractive techniques B81C1/00055

Abstract

Fiber optical devices formed on substrates fabricated with grooves that operate based on evanescent optical coupling through a side-polished fiber surface in each fiber involved. An index-changing liquid is used to control the evanescent optical coupling in response to a control signal.

Claims

1. A device, comprising:

a substrate having an elongated groove formed over a substrate surface;

a fiber having a fiber portion engaged in said elongated groove, a portion of fiber cladding of said fiber portion being removed to form a side fiber surface below said substrate surface by a gap, said side fiber surface spaced from a fiber core of said fiber within a reach of an evanescent field of a guided mode in said fiber;

a high-index layer formed over said substrate surface with a refractive index equal to or greater than an effective refractive index of said fiber; and

an index-changing liquid filled between said high-index layer and said.side fiber surface, said liquid responsive to a control signal to change a refractive index of said liquid.

2. The device as in claim 1, wherein said refractive index of said liquid varies around said refractive index of said fiber cladding.

3. The device as in claim 1, wherein said liquid is responsive to an electromagnetic radiation.

4. The device as in claim 3, wherein said radiation is light.

5. The device as in claim 1, wherein said liquid is responsive to a magnetic field.

6. The device as in claim 1, wherein said liquid is responsive to an electric field.

7. The device as in claim 1, wherein said liquid is responsive to a temperature change.

8. The device as in claim 1, wherein said gap is about 0.5 micron to about 50 microns.

9. The device as in claim 1, wherein said substrate has a through hole penetrating through said substrate and one section of said fiber section passes through said through hole.

10. The device as in claim 1, further comprising a buffer a layer between said fiber and said substrate that has a thermal expansion coefficient between thermal expansion coefficients of said fiber and said substrate.

11. A device, comprising:

a substrate having an array of elongated grooves formed over a substrate surface;

an array of fibers respectively engaged to said elongated grooves;

each fiber having a fiber portion engaged in a respective elongated groove a portion of fiber cladding of said fiber portion being removed to form a side fiber surface below said substrate surface by a gap, said side fiber surface spaced from a fiber core of said fiber within a reach of an evanescent field of a guided mode in said fiber;

a high-index layer formed over-said substrate surface with a refractive index equal to or greater than an effective refractive index of said fiber; and

an index-changing liquid filled between said high-index layer and said side fiber surface of each fiber said liquid responsive to a control signal to change a refractive index of said liquid.

12. The device as in claim 11, wherein said liquid is responsive to an electromagnetic radiation.

13. The device as in claim 11, wherein said liquid is responsive to a magnetic field.

14. The device as in claim 11, wherein said liquid is responsive to an electric field.

15. The device as in claim 11, wherein said liquid is responsive to a temperature change.

16. A device, comprising:

a first substrate having a first elongated groove formed over a first substrate surface;

a first fiber having a fiber portion engaged in said first elongated groove, a portion of fiber cladding of said fiber portion being removed to form a first side fiber surface below said first substrate surface by a gap, said first side fiber surface spaced from a fiber core of said first fiber within a reach of an evanescent field of a guided mode in said first fiber;

a second substrate having a second elongated groove formed over a second substrate surface said second substrate facing said first substrate surface to align said second elongated groove with said first elongated groove;

a second fiber having a fiber portion engaged in said second elongated groove, a portion of fiber cladding of said fiber portion being removed to form a second side fiber surface that does not protrude above said second substrate surface, said second side fiber surface spaced from a fiber core of said second fiber within a reach of an evanescent field of a guided mode in said second fiber and a reach of said evanescent field of said guided mode in said first fiber; and

an index-changing liquid filled between said first and said second fibers, said liquid responsive to a control signal to change a refractive index of said liquid.

17. The device as in claim 16, wherein said liquid is responsive to an electromagnetic radiation.

18. The device as in claim 16, wherein said liquid is responsive to a magnetic field.

19. The device as in claim 16, wherein said liquid is responsive to an electric field.

20. The device as in claim 16, wherein said liquid is responsive to a temperature change.

21. A device, comprising:

a first substrate having a first groove array of elongated grooves formed over a first substrate surface;

a first fiber array of fibers respective engaged to said elongate grooves in said first groove array, each fiber having a fiber portion engaged in a respective elongated groove, a portion of fiber cladding of said fiber portion being removed to form a first side fiber surface below said first substrate surface by a gap, said first side fiber surface spaced from a fiber core of said each fiber within a reach of an evanescent field of a guided mode in said each fiber;

a second substrate having a second groove array of elongated grooves formed over a second substrate surface, said second substrate facing, said first substrate surface to respectively align said elongated grooves in said second groove array with said elongated grooves in said first groove array;

a second fiber array of fibers respectively engaged to said elongated grooves in said second groove array, each fiber having a fiber portion engaged in said second elongated groove, a portion of fiber cladding of said fiber portion being removed to form a second side fiber surface that does not protrude above said second substrate surface, said second side fiber surface spaced from a fiber core of said each fiber within a reach of an evanescent field of a guided mode in said each fiber and a reach of said evanescent field of said guided mode in an aligned fiber in said first fiber array in said first substrate; and

an index-changing liquid filled between each pair of a fiber in said first fiber array and a corresponding fiber in said second fiber array, said liquid responsive to a control signal to change a refractive index of said liquid.