MEMS tunable silicon fabry-perot cavity and applications thereof

• US 8,174,698 B2
• Filed: 08/11/2008
• Issued: 05/08/2012
• Est. Priority Date: 08/10/2007
• Status: Active Grant

• Current Assignee: Polyvalor LP
• Original Assignee: Corporation De L'Ecole Polytechnique De Montreal
• Inventors: Peter, Yves-Alain, Masson, Jonathan, St-Gelais, Raphaël
• Primary Examiner(s): Ton, Tri T
• Application Number:
  US12/228,175
• Publication Number:
  US 20090153844A1
• Time in Patent Office: 1,366 Days
• Field of Search: 356432-448, 356128-132, 372/9, 372/20, 359/333, 359/346, 359/337.5, 359/237, 359/238, 359/290, 430/269, 430/322, 430/323, 216/24
• US Class Current: 356/432
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/41 Refractivity; Phase-affecting properties, e.g. optical path length G01N21/21 takes precedence
• CPC Class Codes: G02B 26/001 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 Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/29376 coupling light guides for controlling wavelength dispersion, e.g. by concatenation of two light guides having different dispersion properties dispersion managed optical transmission systems H04B10/25253
• CPC Class Codes: G02B 6/29394 Compensating wavelength dispersion G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507
• 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 3/06791 Fibre ring lasers fibre laser gyrometers G01C19/72
• CPC Class Codes: H01S 3/08027 by a filter, e.g. a Fabry-Perot filter is used for wavelength setting
• CPC Class Codes: H01S 3/1062 using a controlled passive interferometer, e.g. a Fabry-Perot etalon

Abstract

A method for fabricating a tunable Fabry-Perot cavity comprises etching a substrate to form two reflectors separated by an air gap and an electrostatic mechanism. One of the two reflectors is mobile and connected to the electrostatic mechanism. Therefore, operation of the electrostatic mechanism moves the mobile reflector to change the thickness of the air gap and thereby tune the Fabry-Perot cavity. A tunable Fabry-Perot cavity fabricated with the above method comprises: a substrate; two reflectors formed in the substrate and separated by an air gap having a thickness, wherein one of the two reflectors is mobile; and an electrostatic mechanism formed in the substrate and connected to the mobile reflector. The mobile reflector connected to the electrostatic mechanism is moved upon operation of the electrostatic mechanism to change the thickness of the air gap and thereby tune the Fabry-Perot cavity. Applications of the Fabry-Perot cavity may comprise a tunable doped fiber laser, a tunable dispersion compensator and an integrated microfluidic refractometer.

Claims

1. An integrated microfluidic refractometer for measuring a refractive index of a fluid, the refractometer comprising:

a Fabry-Perot cavity having layers of silicon vertically through a plane of a substrate, the Fabry-Perot cavity comprising two reflectors each comprising three layers of silicon, wherein, in each reflector, a first layer of air is disposed between a first and a second of the layers of silicon and a second layer of air is disposed between the second and a third of the layers of silicon; and

a microfluidic channel, horizontally formed in the plane of the substrate and connected to the Fabry-Perot cavity, for carrying the fluid to the Fabry-Perot cavity, wherein the microfluidic channel and the Fabry-Perot cavity are coplanar within the substrate;

wherein the Fabry-Perot cavity detects a shift of wavelength corresponding to a variation of the refractive index when the fluid passes through the Fabry-Perot cavity.

2. An integrated microfluidic refractometer as defined in claim 1, further comprising a reservoir for containing the fluid to be measured.

3. An integrated microfluidic refractometer as defined in claim 1, wherein the microfluidic channel uses a capillary effect to carry the fluid to the tunable Fabry-Perot cavity.

4. An integrated microfluidic refractometer as defined in claim 1, wherein the refractometer is fabricated through a single photolithography and etching process.

5. An integrated microfluidic refractometer as defined in claim 4, wherein the etching process comprises an optimized bosch processs.