Monolithic physically displaceable optical waveguides

Patent metadata

Field	Value
Publication number	US-2016266331-A1
Application number	US-201314917933-A
Country	US
Kind code	A1
Filing date	Dec 3, 2013
Priority date	Dec 3, 2013
Publication date	Sep 15, 2016
Grant date	—

Abstract

A portion of an optical waveguide extending laterally within a photonic integrated circuit (PIC) chip is at least partially freed from the substrate to allow physical displacement of a released waveguide end relative to the substrate and relative to an adjacent photonic device also fabricated in the substrate. The released waveguide end may be displaced to modulate interaction between the photonic device and an optical mode propagated by the waveguide. In embodiments where the photonic device is an optical coupler, employing for example an Echelle grating or arrayed waveguide grating (AWG), mode propagation through the coupler may be modulated via physical displacement of the released waveguide end. In one such embodiment, thermal sensitivity of an integrated optical wavelength division multiplexer (WDM) is reduced by displacing the released waveguide end relative to the coupler in a manner that counters a temperature dependence of the optical coupler.

First claim

What is claimed is:

1 . A monolithic photonic integrated circuit (PIC), comprising:
a substrate; a photonic device disposed over a first region of the substrate; and an optical waveguide disposed over a second region of the substrate, wherein the optical waveguide further comprises:
a substrate-anchored portion; and
a released portion that is displaceable relative to the photonic device.

2 . The monolithic PIC of claim 1 , wherein the photonic device comprises an optical coupler and traversal of an optical mode through the coupler is dependent on a physical position of an end of the released waveguide portion relative to the coupler.

3 . The monolithic PIC of claim 1 , wherein:
the photonic device comprises an optical coupler and a plurality of second waveguides; and the released waveguide portion is to undergo a physical displacement relative to the substrate and coupler sufficient to vary a coupling of an optical mode among the second waveguides.

4 . The monolithic PIC of claim 1 , wherein:
the photonic device has a temperature dependence; and the released waveguide portion is to undergo a degree of deflection relative to the photonic device to at least partially compensate the temperature dependence.

5 . The monolithic PIC of claim 1 , wherein:
the photonic device comprises an optical coupler and a plurality of second waveguides, the optical coupler having a temperature dependent center frequency associated with the second waveguides and a launch point of the coupler; and the released waveguide portion is to undergo a degree of displacement relative to the photonic device sufficient to compensate a drift in the center frequency over a given temperature range by repositioning the launch point as a function of temperature.

6 . The monolithic PIC of claim 1 , wherein the released waveguide portion comprises a first material; and wherein:
a length of the released waveguide portion is asymmetrically clad with one or more second material to induce a deflection in the released waveguide portion relative to the photonic device as a function of temperature; or the released waveguide portion is further coupled to a microelectromechanical actuator disposed over a third region of the substrate.

7 . The PIC of claim 1 , wherein the released waveguide portion comprises a first material; and
wherein a lateral sidewall of the released waveguide portion is clad with one or more second material.

8 . The PIC of claim 1 , further comprising a microelectromechanical actuator disposed over a third region of the substrate, wherein the actuator further comprises:
a released capacitive member affixed to the released waveguide portion; and an anchored capacitive member affixed to the substrate and spaced apart from the released capacitive member by a distance small enough to electrostatically couple to the released capacitive member in response to a drive voltage.

9 . The PIC of claim 1 , wherein an end of the released waveguide portion is separated from the photonic device by a free-space gap having an integer multiple of one half a center frequency to be propagated by the optical waveguide.

10 . The PIC of claim 1 , wherein at least one of:
an end facet of the at least one of the released waveguide portion or the photonic device is angled non-orthogonally to a longitudinal axis of the waveguide; or an antireflective coating (ARC) is disposed the end of an end facet of the at least one of the released waveguide portion; or a point on an end facet of the released waveguide portion is spaced less than 1.0 μm apart from a point on the adjacent sidewall of the optical coupler.

11 . A monolithic optical wavelength division multiplexer/de-multiplexer (WDM), comprising:
a substrate; an optical coupler disposed over a first region of the substrate; a first optical waveguide disposed over a second region of the substrate, wherein a first end of the first waveguide is optically coupled to a first end of the optical coupler, a plurality of second optical waveguides disposed over a third region of the substrate, wherein each of the plurality of second optical waveguides have a first end optically coupled to a second end of the optical coupler; and wherein: at least one of the first waveguide ends is a released end that is spaced apart from the optical coupler by a free-space gap.

12 . The monolithic WDM of claim 11 , wherein:
the optical coupler comprises a planar waveguide and an Echelle grating or an arrayed waveguide grating (AWG); a first length of the waveguide with the released end is mechanically anchored to the substrate, and a second length of the waveguide with the released end is cantilevered over the substrate and spaced apart from the optical coupler by the free space gap.

13 . The monolithic WDM of claim 12 , wherein:
at least a portion of the second length is asymmetrically clad with one or more second material to induce a mechanical deflection along the second length relative to the optical coupler as a function of the difference between a coefficient of thermal expansion of the second material and the that of the waveguide.

14 . The monolithic WDM of claim 12 , wherein:
the second length is further coupled to a microelectromechanical actuator disposed over a fourth region of the substrate.

15 . The WDM of claim 12 , wherein at least one of:
the released end and a nearest end facet of the optical coupler define a Fabry-Perot cavity dimensioned to an integer multiple of one half a center frequency to be propagated by the first waveguide; or an end facet of the released end or an end facet of the optical coupler is angled non-orthogonally to a longitudinal axis of the first waveguide; or an antireflective coating (ARC) is disposed on an end facet of the released end; or a point on an end facet of the released end is spaced less than 1.0 μm apart from a nearest end facet of the optical coupler.

16 . A PIC, comprising:
the optical WDM of claim 11 ; and a plurality of photodetectors or a plurality of lasers disposed over the substrate and optically coupled to second ends of the second optical waveguides.

17 . An electronic device, comprising:
a processor; a memory; and an optical receiver module chip communicatively coupled to at least one of the processor and the memory, wherein the optical receiver module further comprises a monolithic optical wavelength division multiplexer/de-multiplexer (WDM), further comprising:
a substrate;
an optical coupler disposed over a first region of the substrate;
a first optical waveguide disposed over a second region of the substrate, wherein a first end of the first waveguide is optically coupled to a first end of the optical coupler,
a plurality of second optical waveguides disposed over a third region of the substrate, wherein each of the plurality of second optical waveguides have a first end optically coupled to a second end of the optical coupler; and
wherein:
at least one of the first waveguide ends is a released end that is spaced apart from the optical coupler by a free-space gap; and
a plurality of photodetectors or a plurality of lasers disposed over the substrate and optically coupled to second ends of the second optical waveguides.

18 . A method of fabricating a photonic integrated circuit, the method comprising:
receiving a substrate having a semiconductor device layer disposed over a dielectric material layer; patterning the device layer into a photonic device intersecting an optical waveguide; forming a trench thr

Assignees

• Hutchison David N
• Rong Haisheng
• Heck John
• Intel Corp

Inventors

• Hutchison David N
• Rong Haisheng
• Heck John

Classifications

• G02B6/4208

  using non-reciprocal elements or birefringent plates, i.e. quasi-isolators (optical isolators per se G02F1/093, G02F1/0955) · CPC title

• G02B6/14

  Mode converters · CPC title

• G02B6/12004

  Combinations of two or more optical elements · CPC title

• G02B6/4266

  Thermal aspects, temperature control or temperature monitoring (thermal aspect of electrical circuits H05K7/20, H05K5/0213, temperature control in general G05D23/19) · CPC title

• G02B6/12002

  Three-dimensional structures · CPC title