Integrated microelectromechanical wavelength selective switch and method of making same

• US 20070081761A1
• Filed: 10/06/2005
• Published: 04/12/2007
• Est. Priority Date: 10/06/2005
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc., WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Doerr, Christopher, Marom, Dan
• Granted Patent: US 7,283,709 B2
• Time in Patent Office: Days
• US Class Current: 385/16
• CPC Class Codes: G02B 6/12014 characterised by the wavefront splitting or combining section, e.g. grooves or optical elements in a slab waveguide
• CPC Class Codes: G02B 6/12019 characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes coupling integrated waveguide to fibre G02B6/30, to optoelectronic element G02B6/42; monolithic integration of integrated waveguides with other optical elements G02B6/12004
• CPC Class Codes: G02B 6/12033 characterised by means for configuring the device, e.g. moveable element for wavelength tuning switching G02B6/35; thermo-optic devices G02F1/0147
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• 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 fully integrated microelectromechanical (MEMS) 1×K wavelength selective switch (WSS) includes an array of N solid-immersion micromirrors (SIMs) and a K+1 dispersion waveguide arrays that are integrally fabricated together. In one embodiment, the WSS is fabricated in Silicon. In another embodiment, the N actuators of the SIMs are etched in the Silicon layer of a Silicon-on Insulator (SOI) wafer. Thereafter, a Silica layer is deposited on the Silicon layer and the K+1 waveguide arrays and the mirrors for the N SIMs are etched in that Silica layer. In yet another embodiment, the K+1 dispersion waveguide arrays, except for a small portion of the common confocal coupler, are fabricated using a material selected from a group including Silica, sol-gel, polymers, that is deposited on a first wafer selected from a group including Silicon, Saphire, or other glass insulator material and the remaining portion of the common confocal coupler and the N SIMs are fabricated in a Silicon wafer, and the first wafer and Silicon wafer are then butt-coupled together.

Claims

1. An optical apparatus for switching a multi-wave input optical signal of N channels comprising:

a planar integrated lightwave circuit (PLC) including

K+1 input/output waveguides, where K is an integer greater than or equal to one;

K+1 dispersive waveguide arrays, each waveguide array including a coupler coupled to a different one of the K+1 input/output waveguides, an arrayed waveguide grating (AWG) connected at a first end to the coupler and connected at a second end to a first surface of a common confocal coupler; and

an array of N solid-immersion micromirror (SIM) devices, where N is an integer greater than one, each SIM device placed at a different location on a second surface of the common confocal coupler and each SIM device selectably rotatable to reflect the light of one channel received from a first dispersive waveguide array back through a second dispersive waveguide array.

2. The optical switching apparatus of claim 1 wherein the PLC is fabricated using a Silicon-on-insulator wafer.

3. The optical switching apparatus of claim 1

wherein the PLC is fabricated using a Silicon wafer with a thin oxide layer and a Silicon layer deposited thereon, the N actuators of the SIM devices being formed by etching the Silicon layer, and

wherein a Silica layer is deposited on the Silicon layer and both the K+1 waveguide arrays are formed and N mirrors for the SIM devices are etched in the Silica layer.

4. The optical switching apparatus of claim 1 wherein

the K+1 dispersive waveguide arrays, except for a small portion of the common confocal coupler, are fabricated using a material selected from a group including Silica, sol-gel, polymers, that is deposited on a first wafer selected from a group including Silicon, Saphire, or other glass insulator material, and

the remaining portion of the common confocal coupler and the N SIM devices are fabricated in a Silicon wafer, and wherein the first wafer and Silicon wafer are then butt-coupled together to form the PLC.

5. The optical switching apparatus of claim 1 further comprising

K+1 first waveguide arrays, each first waveguide array for coupling an optical signal between a different one of the K+1 input/output waveguides and a different one of the K+1 dispersive waveguide arrays, each first waveguide array having at least two waveguides and having a free-spectral range equal to the channel separation of the input optical signal, the first waveguide array introducing a first dispersion into the input optical signal, and wherein

each of the K+1 dispersive waveguide arrays has a free-spectral range at least equal to the bandwidth of all of the channels of the input optical signal, and wherein each of the K+1 first waveguide arrays produces a second dispersion which adds to the first dispersion introduced to the input optical signal by a corresponding one of the K+1 first waveguide arrays to generate discrete spots, one spot for each of the N channels.

6. A method of fabricating an optical apparatus for switching a multi-wave input optical signal of N channels comprising:

a planar integrated lightwave circuit (PLC) including

K+1 input/output waveguides, where K is an integer greater than or equal to one;

K+1 dispersive waveguide arrays, each waveguide array including a coupler coupled to a different one of the K+1 input/output waveguides, an arrayed waveguide grating (AWG) connected at a first end to the coupler and connected at a second end to a first surface of a common confocal coupler; and

an array of N solid-immersion micromirror (SIM) devices, where N is an integer greater than one, each SIM device placed at a different location on a second surface of the common confocal coupler and each SIM device selectably rotatable to reflect the light of one channel received from a first dispersive waveguide array back through a second dispersive waveguide array, the method comprising the steps of;

starting with a Silicon wafer with a thin oxide layer and a Silicon layer deposited thereon, etching the N actuators of the SIM devices in the Silicon layer,

depositing a Silica layer over the Silicon layer, and

etching both the K+1 waveguide arrays and N mirrors for the SIM devices in the Silica layer.

7. A method of fabricating an optical apparatus for switching a multi-wave input optical signal of N channels comprising:

a planar integrated lightwave circuit (PLC) including

K+1 input/output waveguides, where K is an integer greater than or equal to one;

K+1 dispersive waveguide arrays, each waveguide array including a coupler coupled to a different one of the K+1 input/output waveguides, an arrayed waveguide grating (AWG) connected at a first end to the coupler and connected at a second end to a first surface of a common confocal coupler; and

an array of N solid-immersion micromirror (SIM) devices, where N is an integer greater than one, each SIM device placed at a different location on a second surface of the common confocal coupler and each SIM device selectably rotatable to reflect the light of one channel received from a first dispersive waveguide array back through a second dispersive waveguide array, the method comprising the steps of;

fabricating the K+1 dispersive waveguide arrays, except for a small portion of the common confocal coupler, using a material selected from a group including Silica, sol-gel, polymers, that is deposited on a first wafer selected from a group including Silicon, Saphire, or other glass insulator material,

forming the remaining portion of the common confocal coupler and the N SIMs in a Silicon wafer, and

butt-coupling together the first wafer and Silicon wafer.