Dynamical Fabry-Perot tuneable filter device

Patent metadata

Field	Value
Publication number	US-9246312-B2
Application number	US-201414476838-A
Country	US
Kind code	B2
Filing date	Sep 4, 2014
Priority date	Aug 11, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

A Fabry-Pérot tuneable filter device is described with reflecting elements separated by an optical path length to form an optical resonator cavity. A first actuator means is directly or indirectly coupled with a first reflecting element. And the first actuator means is configured to modulate the optical path length between first and second reflecting elements by a modulation amplitude to thereby sweep the optical resonator cavity through a band of optical resonance frequencies with a sweep frequency of 70 kHz or more. And the mechanical coupling between selected elements of the arrangement is sufficiently low such that when operated at the sweep frequency, the selected elements act as a system of coupled oscillating elements. In addition or alternatively, the first actuator means is directly or indirectly coupled with the first reflecting element so as to substantially drive the first reflecting element only.

First claim

The invention claimed is:

1. A tuneable VCSEL comprising:
a first and a second reflecting element separated by an optical path length to form an optical resonator cavity,
a gain medium provided on top of one of the first and second reflecting elements,
a first actuator means mechanically coupled with one or both of said first and second reflecting elements, said first actuator means being configured to modulate the optical path length between said first and second reflecting elements by a modulation amplitude, said first actuator comprising at least one piezo-electric actuator,
an optical fiber waveguide coupled with one of the reflecting elements configured for coupling light out of the resonator cavity,
wherein the surface of at least one of the first and second reflecting elements has a concave recess formed therein,
wherein the waveguide is in direct contact with one of the reflecting elements, or wherein one of said first and second reflecting elements is formed by an end of said waveguide; and
wherein one of the reflecting elements is formed by a plate, said plate having a free portion that is free to carry out plate vibrations and a supporting portion where the plate is supported.

2. The tuneable VCSEL of claim 1 , wherein the resonator cavity between the two reflecting elements is free of any light guiding medium.

3. The tuneable VCSEL of claim 1 , wherein one of the reflecting elements comprises a polymer layer in which the concave recess is formed and that is coated with a reflecting layer.

4. The tuneable VCSEL of claim 3 , wherein said reflecting layer is a dielectric reflecting layer.

5. The tuneable VCSEL of claim 1 , wherein said gain medium is provided with an anti-reflective coating.

6. The tuneable VCSEL of claim 1 , wherein the free portion is a central portion and the supporting portion is a circumferential portion at least partly surrounding the central portion of the plate, wherein the supporting portion is directly or indirectly supported by the first actuator means.

7. The tuneable VCSEL of claim 6 , wherein the first actuator means is ring-shaped or is comprised of a plurality of actuators arranged along the circumferential portion of said plate.

8. A tuneable VCSEL comprising:
a first and a second reflecting element separated by an optical path length to form an optical resonator cavity,
a gain medium provided on top of one of the first and second reflecting elements,
a first actuator means mechanically coupled with one or both of said first and second reflecting elements, said first actuator means being configured to modulate the optical path length between said first and second reflecting elements by a modulation amplitude, said first actuator comprising at least one piezo-electric actuator,
an optical fiber waveguide coupled with one of the reflecting elements configured for coupling light out of the resonator cavity,
wherein the surface of at least one of the first and second reflecting elements has a concave recess formed therein,
wherein the waveguide is in direct contact with one of the reflecting elements, or wherein one of said first and second reflecting elements is formed by an end of said waveguide; and
wherein the VCSEL comprises a second actuator means, in particular a second piezo-electric actuator, said second actuator being devised for low frequency actuation such as to compensate drifts in the cavity length, while the first actuator means allows for frequency sweeps in operation.

9. The tuneable VCSEL of claim 8 , wherein the free spectral range of the VCSEL is larger than 1 nm.

10. The tuneable VCSEL of claim 9 , wherein the free spectral range of the VCSEL is larger than 30 nm.

11. The tuneable VCSEL of claim 10 , wherein the free spectral range of the VCSEL is larger than 80 nm.

12. The tuneable VCSEL of claim 8 , wherein the center wavelength of the tuneable VCSEL is chosen among one of the following ranges: 750-870 nm, 1000-1100 nm, 1250-1350 nm and 1480-1600 nm.

13. The tuneable VCSEL of claim 8 , wherein said VCSEL allows for a sweep frequency of a frequency tuning of at least 1 kHz.

14. The tuneable VCSEL of claim 13 , wherein said VCSEL allows for a sweep frequency of a frequency tuning of at least 50 kHz.

15. The tuneable VCSEL of claim 8 , wherein the tuneable VCSEL is operated in an inert gas atmosphere or in a vacuum.

16. The tuneable VCSEL of claim 8 , wherein the gain medium is optically pumped using pump light that is generated by a laser diode.

17. The tuneable VCSEL of claim 8 , wherein the concave recess is provided directly in an end of the fiber, said fiber end forming one of said first and second reflecting elements.

Assignees

• Univ Muenchen Ludwig Maximilians

Inventors

• Huber Robert
• Wieser Wolfgang
• Klein Thomas
• Eigenwillig Christoph
• Biedermann Benjamin
• Muellner Dieter
• Eder Michael

Classifications

• H01S5/423 Primary

  having a vertical cavity · CPC title

• G02B26/001

  based on interference in an adjustable optical cavity (interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26) · CPC title

• H01S5/02284

  Electricity · mapped topic

• H01S3/105

  by controlling the mutual position or the reflecting properties of the reflectors of the cavity {, e.g. by controlling the cavity length}({H01S3/10076}, H01S3/13 take precedence) · CPC title

• G01J3/26 Primary

  using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters · CPC title