Optical steering element and method

• US 7,239,774 B1
• Filed: 08/13/2004
• Issued: 07/03/2007
• Est. Priority Date: 08/13/2004
• Status: Active Grant

• Current Assignee: NeoPhotonics Corporation (Lumentum Holdings Inc.)
• Original Assignee: Lightconnect, Inc. (Lumentum Holdings Inc.)
• Inventors: Nee, Jocelyn, Stowe, Timothy D, Godil, Asif A
• Primary Examiner(s): Pak; Sung
• Assistant Examiner(s): Rahll; Jerry T
• Application Number:
  US10/918,572
• Time in Patent Office: 1,054 Days
• Field of Search: 385/19
• US Class Current: 385/19
• CPC Class Codes: G02B 6/2713 cascade of polarisation selective or adjusting operations
• CPC Class Codes: G02B 6/2793 Controlling polarisation dependent loss, e.g. polarisation insensitivity, reducing the change in polarisation degree of the output light even if the input polarisation state fluctuates
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29311 Diffractive element operating in transmission
• CPC Class Codes: G02B 6/29313 characterised by means for controlling the position or direction of light incident to or leaving the diffractive element, e.g. for varying the wavelength response switching G02B6/35
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: G02B 6/29391 Power equalisation of different channels, e.g. power flattening
• CPC Class Codes: G02B 6/29397 Polarisation insensitivity
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001

Abstract

A 1×N wavelength selective switch which can function as a dynamic channel equalizer when N=1. In an exemplary arrangement, the present invention is a free-space device that includes a linear array of micromachined reflective elements for beam steering of individual wavelength channels. In at least some embodiments the array of reflective elements of the present invention provides a substantially seamless design such that the optical spectrum appears flat across the transition between actuators. Various embodiments provide high channel bandwidth with flat-top channel performance, low polarization dependence loss, low vibration sensitivity, extinction ratios greater than 40 dB over all temperatures, and very low levels of electrical and optical channel cross-talk.

Claims

1. A free space 1×

N wavelength selective switch comprising;

an input port for receiving an input beam,

an output port for transmitting an output beam,

a grating for separating the input beam into individual wavelengths,

at least one reflective element, each reflective element including a stator and having a length and a width,

a rotor positioned on a substrate and configured to electrically interact with the stator upon the application of an electrostatic force therebetween,

the stator and rotor each having interdigitated elements arranged orthogonally to the length of the reflective element,

optical beam guiding components for receiving the input beam and directing the beam to the at least one reflective element and then to the output port as an output beam,

wherein N is equal to 1 and the switch operates as a dynamic channel equalizer.

2. A free space 1×

N wavelength selective switch comprising

an input port for receiving an input beam,

an output port for transmitting an output beam,

a grating for separating the input beam into individual wavelengths,

at least one reflective element, each reflective element including a stator and having a length and a width,

a rotor positioned on a substrate and configured to electrically interact with the stator upon the application of an electrostatic force there between,

the stator and rotor each having interdigitated elements arranged orthogonally to the length of the reflective element,

optical beam guiding components for receiving the input beam and directing the beam to the at least one reflective element and then to the output port as an output beam,

wherein the interdigitated elements on the stator are fingers,

wherein the movement of the reflective element is rotation about an axis and the interdigitated fingers are oriented parallel to the axis of rotation.

3. A seamless wavelength selective switch comprising

an input port for receiving an input beam,

an output port for transmitting an output beam,

a plurality of reflective elements, each reflective element including a stator and having a length and a width,

a rotor positioned on a substrate and configured to electrically interact with the stator upon the application of an electrostatic force therebetween,

a hinge operatively affixed to the reflective element and to the substrate to permit the reflective element to move upon the application of an electrostatic force applied to the stator and rotor,

a plurality of slots in the reflective elements to form a periodic amplitude grating to mask transitions between channels, and

optical beam guiding components for receiving the input beam and directing the beam to the linear array and then to the output port as an output beam.

4. The wavelength selective switch of claim 3 further comprising a plurality of traces for conducting electrical signals wherein the traces are not positioned underneath the reflective region.

5. A free space 1×

N wavelength selective switch comprising;

an input port for receiving an input beam,

an output port for transmitting an output beam,

at least one reflective element, each reflective element including a stator and having a length and a width,

a rotor positioned on a substrate and configured to electrically interact with the stator upon the application of an electrostatic force therebetween,

the stator and rotor each having interdigitated elements arranged orthogonally to the length of the reflective element,

a post affixed to the substrate, and a hinge associated with the at least one reflective element and affixed to the post to allow the at least one reflective element to move in response to an electrostatic force applied between the stator and the rotor, and,

optical beam guiding components for receiving the input beam and directing the beam to the at least one reflective element and then to the output port as an output beam.

6. The wavelength selective switch of claim 5 further comprising a plurality of posts, and a plurality of reflective elements connected thereto to create a linear array.

7. The wavelength selective switch of claim 5 further including a stopper to prevent mechanical interference between the stator and the rotor.

8. The wavelength selective switch of claim 5 wherein a single post provides support for two hinges and their associated reflective elements.

9. The wavelength selective switch of claim 8 wherein the reflective elements are disposed symmetrically about the hinge.

10. The wavelength selective switch of claim 8 wherein a fill ratio in excess of 90 percent is achieved.