Frequency tunable waveguide extended cavity laser

• US 5,418,802 A
• Filed: 11/12/1993
• Issued: 05/23/1995
• Est. Priority Date: 11/12/1993
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Chwalek, James M.
• Primary Examiner(s): Scott, Jr., Leon
• Application Number:
  US08/152,559
• Time in Patent Office: 557 Days
• Field of Search: 372/18, 372/64, 372/22, 372/99, 372/21, 372/96, 372/97, 372/20, 372/102, 372/32
• US Class Current: 372/20
• CPC Class Codes: G02F 1/035 in an optical waveguide structure
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: H01S 3/1055 one of the reflectors being constituted by a diffraction grating
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 5/0092 for nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity
• CPC Class Codes: H01S 5/141 using a wavelength selective device, e.g. a grating or etalon H01S5/146 takes precedence

Abstract

A frequency tunable waveguide extended cavity laser formed with a laser diode, a channel waveguide comprising an electro-optic material, a frequency tunable Bragg grating reflector formed in or on the channel waveguide and a pair of conducting electrodes. The frequency of radiation produced by the frequency tunable waveguide extended cavity laser is adjusted so as to be at a desired frequency by applying a voltage to the conducting electrodes. The device further incorporates a waveguide nonlinear optical frequency converter to produce frequency convened radiation at a higher frequency. Feedback means are included for dynamically controlling the desired frequency so as to be at a frequency for optimum frequency conversion.

Claims

1. A frequency tunable waveguide extended cavity laser producing radiation at a desired frequency comprising:

a) a laser diode having a reflecting rear facet and a front facet for emitting radiation;

b) a channel waveguide for receiving radiation from said front facet of said laser diode, a portion of said channel waveguide having an electro-optical material in the waveguide channel that undergoes a refractive index change in response to an applied electric field;

c) a Bragg grating reflector formed relative to said channel waveguide portion having said electro-optical material; and

d) means for applying an adjustable electric field to said Bragg grating reflector to change the refractive index of said electro-optic material so as to be at a desired frequency.

2. The device of claim 1 wherein the front facet of said laser diode is coated with a partially reflective coating.

3. The device of claim 1 wherein the front facet of said laser diode is coated with an anti-reflective coating.

4. The device of claim 1 wherein said Bragg grating reflector is composed of said electro-optic material.

5. The device of claim 1 wherein said Bragg grating reflector is composed of an optically transparent inorganic material positioned on the surface of said channel waveguide.

6. The device of claim 1 wherein said Bragg grating reflector is composed of an optically transparent organic material positioned on the surface of said channel waveguide.

7. The device of claim 1 wherein said means for applying an adjustable electric field to said Bragg grating reflector comprises an adjustable voltage system and a pair of conducting electrodes which surround said Bragg grating reflector.

8. A frequency tunable waveguide extended cavity laser producing radiation at a desired frequency comprising:

a) a laser diode having a reflecting rear facet and a front facet for emitting radiation;

b) a channel waveguide for receiving radiation from said front facet of said laser diode, a portion of said channel waveguide having an electro-optical material in the waveguide channel that undergoes a refractive index change in response to an applied electric field;

c) a Bragg grating reflector formed relative to said channel waveguide portion having said electro-optical material;

d) means for applying an adjustable electric field to said Bragg grating reflector to change the refractive index of said electro-optic material so as to be at a desired frequency;

e) a nonlinear optical frequency convening waveguide portion having a nonlinear optical material which converts the frequency of said desired frequency to a higher frequency; and

f) detection means opto-electronically responsive to the frequency converted radiation for continuously measuring the frequency converted radiation power, and feedback means for dynamically controlling said desired frequency so as to be at a frequency for optimum frequency conversion.

9. The device of claim 8 wherein the front facet of said laser diode is coated with a partially reflective coating.

10. The device of claim 8 wherein tile front facet of said laser diode is coated with an anti-reflective coating.

11. The device of claim 8 wherein said Bragg grating reflector is composed of said electro-optic material.

12. The device of claim 8 wherein said Bragg grating reflector is composed of an optically transparent inorganic material positioned on the surface of said channel waveguide.

13. The device of claim 8 wherein said Bragg grating reflector is composed of an optically transparent organic material positioned on the surface of said channel waveguide.

14. The device of claim 8 wherein said means for applying an adjustable electric field to said Bragg grating reflector comprises an adjustable voltage system and a pair of conducting electrodes which surround said Bragg grating reflector.

15. The device of claim 8 wherein said electro-optic material and said nonlinear optical material are the same material.

16. A frequency tunable waveguide extended cavity laser producing radiation at a desired frequency comprising:

a) a laser diode having a reflecting rear facet and a front facet for emitting radiation;

b) a channel waveguide for receiving radiation from said front facet of said laser diode, a portion of said channel waveguide having an electro-optical material in the waveguide channel that undergoes a refractive index change in response to an applied electric field;

c) a Bragg grating reflector formed relative to said channel waveguide portion having said electro-optical material;

d) a nonlinear optical frequency converting waveguide portion having a nonlinear optical material which converts the frequency of said desired frequency to a higher frequency and for which said nonlinear optical frequency converting waveguide portion is located in between said laser diode and said Bragg grating reflector;

e) means for applying an adjustable electric field to said Bragg grating reflector to change the refractive index of said electro-optic material so as to be at a desired frequency; and

f) detection means opto-electronically responsive to the frequency converted radiation for continuously measuring the frequency converted radiation power, and feedback means for dynamically controlling said desired frequency so as to be at a frequency for optimum frequency conversion.

17. The device of claim 16 wherein the front facet of said laser diode is coated with a partially reflective coating.

18. The device of claim 16 wherein the front facet of said laser diode is coated with an anti-reflective coating.

19. The device of claim 16 wherein said Bragg grating reflector is composed of said electro-optic material.

20. The device of claim 16 wherein said Bragg grating reflector is composed of an optically transparent inorganic material positioned on the surface of said channel waveguide.

21. The device of claim 16 wherein said Bragg grating reflector is composed of an optically transparent organic material positioned on the surface of said channel waveguide.

22. The device of claim 16 wherein said means for applying an adjustable electric field to said Bragg grating reflector includes an adjustable voltage system and a pair of conducting electrodes which surround said Bragg grating reflector.

23. The device of claim 16 wherein said electro-optic material and said nonlinear optical material are the same material.