Tunable bragg grating and devices employing the same

• US 6,534,248 B2
• Filed: 01/24/2001
• Issued: 03/18/2003
• Est. Priority Date: 02/09/1998
• Status: Expired

• Current Assignee: UNM Rainforest Innovations (f/k/a STC.UNM) (The University of New Mexico)
• Original Assignee: Agency For Science Technology and Research (Government of Singapore)
• Inventors: Srinivasan, Balaji, Jain, Ravinder
• Primary Examiner(s): ANGEBRANNDT, MARTIN J
• Application Number:
  US09/768,048
• Publication Number:
  US 20020119400A1
• Time in Patent Office: 783 Days
• Field of Search: 430/321, 430/326, 385/8, 385/10, 385/40, 385/123, 216/24, 216/37
• US Class Current: 430/321
• CPC Class Codes: G02B 6/02195 characterised by means for tuning the grating
• CPC Class Codes: G02B 6/022 using mechanical stress, e.g. tuning by compression or elongation, special geometrical shapes such as "dog-bone" or taper G02B6/02204 takes precedence; optical modulation using photo-elastic effect G02F1/0131
• CPC Class Codes: G02B 6/274 based on light guide birefringence, e.g. due to coupling between light guides G02B6/105, G02B6/024 take precedence; mechanically induced birefringence G02F1/0134
• CPC Class Codes: G02B 6/2746 comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators magneto-optic non-reciprocal devices G02F1/093
• CPC Class Codes: G02B 6/29322 Diffractive elements of the tunable type G02B6/02195 takes precedence; optical modulation devices based on a change of the optical properties of the medium G02F1/00
• CPC Class Codes: G02B 6/29353 with a wavelength selective element in at least one light guide interferometer arm, e.g. grating, interference filter, resonator
• CPC Class Codes: G02B 6/29355 Cascade arrangement of interferometers
• CPC Class Codes: G02B 6/4207 with optical elements reducing the sensitivity to optical feedback anti-reflection devices specially adapted for lasers, see H01S3/0064
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/0115 in optical fibres
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 1/215 Michelson type
• CPC Class Codes: G02F 1/3558 Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: G02F 2202/06 dopant
• CPC Class Codes: G02F 2202/07 poled
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G02F 2203/07 Polarisation dependent
• CPC Class Codes: G02F 2203/585 Add/drop devices
• CPC Class Codes: G02F 2203/62 Switchable arrangements whereby the element being usually not switchable
• CPC Class Codes: H01S 3/0675 : Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• CPC Class Codes: H01S 3/105 : by controlling the mutual position or the reflecting properties of the reflectors of the cavity , e.g. by controlling the cavity lengthH01S3/10076, H01S3/13 take precedence

Abstract

The present invention relates generally to electro-optically active waveguide segments, and more particularly to the use of a selective voltage input to control the phase, frequency and/or amplitude of a propagating wave in the waveguide. Particular device structures and methods of manufacturing are described herein.

Claims

1. A method for manufacturing an electro-optic waveguide segment having a core and a cladding;

the method comprising the steps of;

forming a Bragg grating in said waveguide segment;

removing a first selective portion of said cladding above at least a portion of said Bragg grating to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;

depositing a first electrically conductive material covering at least part of said first selective portion and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;

removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one-another;

depositing a second electrically conductive material covering at least part of said second selective portion and in direct contact with a deepest portion of said of said second recess, thereby forming a second electrode, wherein there are substantially no air gaps between said second electrode and said second recess; and

poling said waveguide segment using at least a electric field applied to either said first or second electrode to induce an non-linearity in said waveguide segment.

2. The method recited in claim 1, wherein said first recess is substantially filled with said first electrically conductive material.

3. The method rccitcd in claim 2, wherein said first electrically conductive material is optically transparent.

4. The method recited in claim 1, wherein said second recess is substantially filled with a second electrically conductive material.

5. The method recited in claim 4, wherein said second electrically conductivc material is optically transparent.

6. The method recited in claim 1 wherein said poling step is performed using ultraviolet light injected into said waveguide segment in combination with said electric field.

7. The method recited in claim 1, wherein said poling step is performed using said electrical field in combination with heating said waveguide segment.

8. A method for manufacturing an electro-optic waveguide segment having a core and a cladding;

the method comprising the steps of;

forming a Bragg grating in said waveguide segment;

removing a first selective portion of said cladding above at least a portion of said Bragg grating to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;

depositing a first electrically conductive material covering at least part of said first selective portion and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;

removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one-another;

depositing a second electrically conductive material covering at least part of said second selective portion and in direct contact with a deepest portion of said second recess, thereby forming a second electrode, wherein there are substantially no air gaps between said second electrode and said second recess; and

poling said waveguide segment using ultraviolet light injected into said waveguide segment to induce an non-linearity in said waveguide.

9. A method for manufacturing an electro-optic waveguide segment having a core and a cladding;

the method comprising the steps of;

forming a Bragg grating in said waveguide segment;

removing a first selective portion of said cladding above at least a portion of said Bragg grating to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;

depositing a first electrically conductive material covering at least part of said first selective portion and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;

removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one-another;

depositing a second electrically conductive material covering at least part of said second selective portion and in direct contact with a deepest portion of said second recess; and

poling said waveguide segment by heating said waveguide segment in combination with ultraviolet light injected into said waveguide segment to induce an non-linearity in said waveguide segment.

10. A method for manufacturing an electro-optic waveguide segment having a core and a cladding;

the method comprising the steps of;

removing a first selective portion of said cladding to form a first recess within said cladding, said first selective portion having an outer dimension which is less than an unmodified section of said cladding;

removing a second selective portion of said cladding to form a second recess within said cladding, said second selective portion having an outer dimension which is less than an unmodified section of said cladding, said first and second selected portions not contacting one another;

depositing a first electrically conductive material within said first recess and in direct contact with a deepest portion of said first recess, thereby forming a first electrode, wherein there are substantially no air gaps between said first electrode and said first recess;

depositing a second electrically conductive material within said second recess and in direct contact with a deepest portion of said second recess, thereby forming a second electrode, wherein there are substantially no air gaps between said second electrode and said second recess; and

poling said waveguide segment using at least a electric field applied to said first and second selective portions to induce a non-linearity in said waveguide segment.

11. The method for manufacturing recited in claim 10, further comprising the step of forming a Bragg grating in said waveguide segment.