Electrically tunable fabry-perot structure utilizing a deformable multi-layer mirror and method of making the same

• US 6,597,490 B2
• Filed: 11/27/2001
• Issued: 07/22/2003
• Est. Priority Date: 09/29/1995
• Status: Expired due to Fees

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Coretek, Inc. (Nortel Networks Corporation)
• Inventors: Tayebati, Parvis
• Primary Examiner(s): Ip, Paul
• Assistant Examiner(s): MENEFEE, JAMES A
• Application Number:
  US09/994,572
• Publication Number:
  US 20020126725A1
• Time in Patent Office: 602 Days
• Field of Search: 359/291, 372/20, 372/99, 372/43-46
• US Class Current: 359/291
• 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 26/002 the movement or the deformation controlling the frequency of light, e.g. by Doppler effect
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H01S 5/0614 controlled by electric field, i.e. whereby an additional electric field is used to tune the bandgap, e.g. using the Stark-effect
• CPC Class Codes: H01S 5/18363 comprising air layers
• CPC Class Codes: H01S 5/18366 Membrane DBR, i.e. a movable DBR on top of the VCSEL
• CPC Class Codes: H01S 5/18372 by native oxidation

Abstract

An electrically tunable Fabry-Perot structure using a deformable multi-layer mirror construction wherein Ga_1−aAl_aAs, where a<0.1, is used as the sacrificial layer which may be selectively removed using a citric acid enchant. The multi-layer mirrors consist of N and M period of quarter wavelength layers where N and M are integers, or integers plus ½. Further, the mirrors are made from alternating layers of Ga_1−xAl_xAs, where x>0.96, and a material selected from the group consisting of either Ga_1−zAl_zAs, where 0.7>Z>0, or Ga_1−yAl_yAs/Ga_1−zAl_zAs/Ga_1−yAl_yAs, where 0.7>Z>0 and y>0.5. The Ga_1−xAl_xAs is wet oxidized by exposing its edge to water in a nitrogen or helium atmosphere at a temperature of between about 360° C. and 450° C. so as to transform it to AlO_x. The resulting AlO_x layers abut the sacrificial layer and act as etch stops during the formation of a cantilever Fabry-Perot structure by etching of the sacrificial layer.

Claims

1. An electrically tunable optical filter comprising:

a laterally-extending base comprising an optically-transparent GaAs material;

a first laterally-extending mirror comprising alternating layers of (i) a material selected from the group consisting of GaAs;

GaAlAs; and

Ga<sub>1−

y</sub>Al_yAs/Ga<sub>1−

z</sub>Al_zAs/Ga<sub>1−

y</sub>Al_yAs where y>

0.5 and Z<

0.7, and (ii) AlO_x;

a second laterally-extending mirror comprising alternating layers of (i) a material selected from the group consisting of GaAs;

GaAlAs; and

Ga<sub>1−

y</sub>Al_yAs/Ga<sub>1−

z</sub>Al_zAs/Ga<sub>1−

y</sub>Al_yAs where y>

0.5 and Z<

0.7, and (ii) AlO_x;

said first laterally-extending mirror being fixedly mounted to said laterally extending base;

said second laterally-extending mirror being movably mounted to said first laterally-extending mirror such that an air gap extends between said first laterally-extending mirror and said second laterally-extending mirror;

a first electrode electrically connected to said first laterally-extending mirror; and

a second electrode electrically connected to said second laterally-extending mirror;

whereby when a voltage difference is applied across said first and second electrodes, the electrically tunable optical filter will change its spectral response.