Devices based on fibers engaged to substrates with grooves

• US 6,490,391 B1
• Filed: 07/12/2001
• Issued: 12/03/2002
• Est. Priority Date: 07/12/2000
• Status: Expired due to Term

• 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 E.
• Assistant Examiner(s): Doan, Jennifer
• Application Number:
  US09/905,038
• Time in Patent Office: 509 Days
• Field of Search: 385/15, 385/18, 385/24, 385/25, 385/27, 385/28, 385/30, 385/31, 385/32, 385/39, 385/42, 385/47, 385/50, 385/65, 385/83, 385/129-132, 385/147
• US Class Current: 385/30
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• 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 6/29332 Wavelength selective couplers, i.e. based on evanescent coupling between light guides, e.g. fused fibre couplers with transverse coupling between fibres having different propagation constant wavelength dependency non wavelength-selective light guide couplers G02B6/28
• CPC Class Codes: G02B 6/2934 Fibre ring resonators, e.g. fibre coils
• CPC Class Codes: G02B 6/29355 Cascade arrangement of interferometers
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• 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 6/3536 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 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3636 the mechanical coupling means being grooves G02B6/3652 takes precedence
• 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.

Claims

1. A device, comprising:

a fiber ring forming a closed optical loop to circulate optical energy and having at least a first fiber coupling port which is formed by removing a portion of fiber cladding to form an optical surface within a reach of an evanescent field of a guided mode in said fiber ring;

a first substrate engaged to said fiber ring and having a first substrate surface where said first fiber coupling port is located;

a fiber having a second fiber coupling port which is formed by removing a portion of fiber cladding to form an optical surface within a reach of an evanescent field of a guided mode in said fiber,

a second substrate engaged to said fiber and having a second substrate surface where said second fiber coupling port is located and which faces said first substrate surface of said first substrate, wherein said second substrate is positioned to align said first and said second fiber coupling ports to allow for evanescent coupling therebetween.

2. The device as in claim 1, wherein at least one substrate has an elongated groove to which a fiber section is engaged and a respective fiber coupling port is formed.

3. The device as in claim 2, wherein said substrate has a through hole penetrating through said substrate and one section of said fiber section passes through said through hole.

4. The device as in claim 1, wherein said fiber ring has a third fiber coupling port, and further comprising a second fiber engaged to said second substrate and having a fourth fiber coupling port located to couple evanescently with said third fiber coupling port.

5. An optical device, comprising:

a first fiber having a first fiber coupling port which is formed by removing a portion of fiber cladding to form an optical surface within a reach of an evanescent field of a guided mode in said first fiber;

a first substrate engaged to said first fiber and having a first substrate surface where said first fiber coupling port is located;

a second fiber having a second fiber coupling port which is formed by removing a portion of fiber cladding to form an optical surface within a reach of an evanescent field of a guided mode in said second fiber; and

a second substrate engaged to said second fiber and having a second substrate surface where said second fiber coupling port is located and which faces said first substrate surface of said first substrate, said second substrate positioned to align said first and said second fiber coupling ports to allow for evanescent coupling therebetween,

wherein said first fiber coupling port is responsive to a control signal to change said evanescent coupling, and

wherein said wherein at least one substrate has an elongated groove to which a fiber section is engaged and a respective fiber coupling port is formed, and wherein said substrate has a through hole penetrating through said substrate and one section of said fiber section passes through said through hole.

6. The device as in claim 5, wherein said first fiber coupling port changes a property in response to a change in temperature.

7. The device as in claim 5, wherein said first fiber coupling changes property in response to an electrical field.

8. The device as in claim 5, wherein said first fiber coupling port changes at least a refractive index in response to said control signal.

9. The device as in claim 5, wherein said first fiber coupling port changes at least a length in response to said control signal.

10. The device as in claim 5, wherein said second fiber coupling port is also responsive to another control signal to change said evanescent coupling.

11. A device, comprising:

first and second fiber modules respectively formed on first and second substrates and respectively having first and second optical fibers,

wherein a respective substrate in each fiber module comprises (1) first and second opposing substrate surfaces, (2) a first elongated groove formed over said first substrate surface, (3) at least one opening located at one end of said first elongated groove and formed through said substrate to extend between said first and second substrate surfaces, (4) a second elongated groove formed over said first substrate surface, and (5) a second opening located at one end of said second elongated groove and formed through said substrate to extend between said first and second substrate surfaces,

wherein a respective optical fiber in each fiber module is engaged to said respective substrate to pass through said first and said second openings to have a first fiber portion in said first elongated groove, a second fiber portion in said second elongated groove, and a third fiber portion between said first and said second fiber portions positioned over said second substrate surface, and wherein fiber claddings of said first and said second fiber portions are removed to form first and second fiber coupling ports for evanescent coupling into or out of said respective optical fiber,

wherein said first and said second fiber modules are positioned to have said first substrate surfaces face each other where said first and said second optical coupling ports of said first optical fiber are respectively coupled to said first and said second optical coupling ports of said second optical fiber to form a Mach-Zehnder interferometer,

wherein said third fiber portion in said first optical fiber includes an adjustable section that is configured to respond to a control signal to cause a change in an optical path length of said third fiber portion, and

wherein at least said first optical coupling port of one of said first and said second fibers is responsive to a control signal to change evanescent coupling.

12. The device as in claim 11, wherein said responsive first fiber coupling port changes a property in response to a change in temperature.

13. The device as in claim 11, wherein said responsive first fiber coupling changes property in response to an electrical field.

14. The device as in claim 11, wherein said responsive first fiber coupling port changes at least a refractive index in response to said control signal.

15. The device as in claim 11, wherein said responsive first fiber coupling port changes at least a length in response to said control signal.

16. A device, comprising:

a first fiber module having a first substrate which includes (1) first and second opposing substrate surfaces, (2) a first elongated groove formed over said first substrate surface, and (3) at least one opening located at one end of said first elongated groove and formed through said first substrate to extend between said first and second substrate surfaces, said first fiber module also having a first fiber passing through said opening to have a first fiber section in said first elongated groove with fiber cladding partially removed to form a first coupling surface within a reach of an evanescent field of a guided mode in said first fiber; and

a second fiber module having (1) a second substrate with a substrate surface facing said first substrate surface of said first substrate and including an elongated groove, and (2) a second fiber engaged in said elongated groove to have a third coupling surface which is formed by removing a portion of fiber cladding and is within a reach of an evanescent field of a guided mode in said second fiber, wherein said second fiber module is positioned to align said third coupling surface to said first coupling surface to allow evanescent coupling between said first and said second fibers.

17. The device as in claim 16, wherein said first fiber includes an adjustable section which changes said evanescent coupling between said first and said third fibers in response to a control signal.

18. The device as in claim 16, wherein said first substrate includes a second elongated groove formed over said second substrate surface and having one end connected to said opening, and wherein said first fiber also has a second fiber section in said second elongated groove with fiber cladding partially removed to form a second coupling surface within a reach of an evanescent field of a guided mode in said first fiber, said device further comprising:

a third fiber module having (1) a third substrate with a substrate surface facing said second substrate surface of said first substrate and including an elongated groove, and (2) a third fiber engaged in said elongated groove to have a fourth coupling surface which is formed by removing a portion of fiber cladding and is within a reach of an evanescent field of a guided mode in said third fiber, wherein said third fiber module is positioned to align said fourth coupling surface to said second coupling surface to allow for evanescent coupling between said first and said third fibers.

19. The device as in claim 18, wherein a coupling ratio between said first and said third fibers is different from a coupling ratio between said first and said second fibers.

20. The device as in claim 18, wherein a coupling ratio between said first and said third fibers is substantially equal to a coupling ratio between said first and said second fibers.

21. A device, comprising:

first and second fiber modules respectively having first and second fibers engaged to first and second substrates, respectively, each fiber module having a substrate which includes (1) first and second opposing substrate surfaces, (2) at least four elongated grooves formed over said first substrate surface and at least one elongated groove formed over said second substrate surface, and (3) a plurality of openings located at ends of said elongated grooves and formed through said substrate to extend between said first and second substrate surfaces and to connect said elongated grooves, wherein each fiber passes through said openings to have fiber portions over both substrate surfaces and to form at least four fiber coupling ports in said elongated grooves on said first substrate and at least a single fiber coupling port on said second substrate surface that is located between first two adjacent fiber coupling ports and second two adjacent fiber coupling ports, wherein each fiber coupling port is formed by partially removing fiber cladding to form a coupling surface within a reach of an evanescent field of a guided mode in said fiber,

wherein said first and said second fiber modules are engaged to face respective first substrate surfaces to each other to form a first Mach-Zehnder interferometer by aligning said first two adjacent fiber coupling ports of said first fiber module to said first two adjacent fiber coupling ports of said second fiber module to allow for evanescent coupling between said first and said second fibers, and a second Mach-Zehnder interferometer by aligning said second two adjacent fiber coupling ports of said first fiber module to said second two adjacent fiber coupling ports of said second fiber module to allow for evanescent coupling between said first and said second fibers;

a third fiber module having (1) a third substrate with a substrate surface facing said second substrate surface of said first substrate and including an elongated groove, and (2) a third fiber engaged in said elongated groove to have a third coupling port which is formed by removing a portion of fiber cladding to form a surface within a reach of an evanescent field of a guided mode in said third fiber, wherein said third fiber module is positioned to align said third coupling port to said single coupling port on said second substrate surface of said first substrate to allow evanescent coupling between said first and said third fibers; and

a fourth fiber module having (1) a fourth substrate with a substrate surface facing said second substrate surface of said second substrate and including an elongated groove, and (2) a fourth fiber engaged in said elongated groove to have a fourth coupling port which is formed by removing a portion of fiber cladding to form a surface within a reach of an evanescent field of a guided mode in said fourth fiber, wherein said fourth fiber module is positioned to align said fourth coupling port to said single coupling port on said second substrate surface of said second substrate to allow for evanescent coupling between said fourth and said second fibers.

22. The device as in claim 21, wherein at least one fiber includes an adjustable fiber section at a respective coupling port, said adjustable fiber section operable to change evanescent coupling of said respective coupling port in response to a control signal.

23. The device as in claim 21, wherein the interfacing region of said fourth coupling port and said single coupling port on said second substrate surface of said second substrate is configured to couple optical energy at a selected wavelength.