Detailed Office Action
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-10
Claims 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over Watts (2017/0315387; “Watts”) in view of Popovic, Milos (2014/0193115; “Popovic”).
Regarding claim 1, Watts discloses in figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text, embodiments of light-emitting devices comprising ‘emitter elements used to form antennae … that results in emitted light that is coherent and emits in a single direction.” Watts, paragraph [0066].
Watts – Figures 2 and 3
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Watts – Figures 4 and 5
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Watts – Figures 11 and 14
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Watts – Selected Text
[0072] The “Tetris-style” approach to an example optical device is illustrated by the unit cell 10, which includes the phase shifter region 12 and the light-emitting region 13 offset from one another in a longitudinal direction defined by the orientation of the waveguides with in the phase shifter region 12 and the light-emitting region 13. The different regions are disposed at different layers within the optical device 1. A phase shifter layer 18 of the optical device 1 includes an array of phase shifter regions (e.g., phase shifter region 12), each phase shifter region comprising a first plurality of waveguides and at least one phase shifter for at least a portion of the first plurality of waveguides. Each phase shifter region of the array of phase shifter regions is located at a respective position within the array of phase shifter regions. An antenna layer 20 of the optical device 1 is above or below the phase shifter layer 18. The antenna layer 20 includes an array of light-emitting regions (e.g., light-emitting region 13), each light-emitting region including a second plurality of waveguides. Each light-emitting region of the array of light-emitting regions is located at a respective position within the array of light-emitting regions. Additionally, each light-emitting region of the array of light-emitting regions is configured to emit light received from a phase shifter region located at a position adjacent to a position of the light-emitting region. For example, phase shifter region 12 is located at a position in the array that is one position to the left of the light-emitting region 13. In other words, the center of the phase shifter region 12 is to the left of the center of the light-emitting region 13. It should be understood, that the directional terms left and right are being used in reference to FIG. 1 and do not limit the directionality of embodiments of the optical device
[0075] Referring to FIG. 2C, an antenna layer 35 is located above a phase shifter layer 37. The antenna layer 35 includes three light-emitting regions 36a-c and the phase-shifter layer 29 includes three phase shifter regions 38a-c, though the number of regions in each layer is not limited to three. Multiple splitting distribution network regions 40a-c are disposed in a splitting network layer 39 that is located at a depth level that is lower than the depth level of the phase shifter layer 37. There are also two transition layers, a first transition layer 41 and a second transition layer 43. The transition layer 41 includes transition regions 42a-c, which each include a plurality of waveguides. The transition layer 43 also includes multiple transition regions 44a-c, which each include a plurality of waveguides. The transition regions provide optical isolation between the phase shifter layer 37 and the antenna 35 by vertically separating these layers in the depth direction such that waveguides in the phase shifter layer 37 do not directly optically couple with waveguides in the antenna layer 35. This prevents cross-talk between the layers. The waveguides in the first transition layer 41 receive light from waveguides in the phase shifter layer 37; the waveguides in the second transition layer 43 receive light from waveguides in the first transition layer 41; the waveguides of the antenna layer 35 receive light from the waveguides of the second transition layer 43. Consequently, the phase shifter layer 37 is located at a depth level that is between the antenna layer 35 and the splitting network layer 39, but the phase shifter layer 37 is separated from the antenna layer 35 by multiple transition layers. While two transition layers are illustrated in FIG. 2C, a single transition layer may be used or more than two transition layers may be used. A unit cell 45 includes a splitting distribution region 40b, a phase shifter region 38b, a first transition region 42b, a second transition region 44b, and a light-emitting region 36b. The light-emitting region 36b is above the phase shifter region 338c of a different unit cell because the waveguides of the light-emitting region 36b receives light, via the transition regions 42b and 44b, from the phase shifter region 38b, which is located at an adjacent position.
[0076] An optical layer transition is used to optically couple a waveguide from a first layer to a waveguide located in a second layer that is above or below the first layer. Non-limiting examples of optical layer transitions include an inverse taper element, a grating-to-grating coupler, or a periscope. The periscope includes an arrangement of at least two reflective surfaces that guide light from the waveguide of the first layer to the waveguide of the second layer using reflection. An example of an inverse taper element is an “optical escalator.” Referring to FIG. 1F, an optical escalator 16 includes a first waveguide 17 at a first depth level and a second waveguide 18 at a second depth level. The first waveguide 17 is tapered such that the width of the first waveguide 17 decreases from a first width to a termination width at which the first waveguide 17 terminates. The second waveguide 18 is tapered in the opposite direction of the first waveguide 17 such that the width of the second waveguide 18 begins with an initial width and grows into a waveguide with a second width. The first waveguide 17 and the second waveguide 18 overlap vertically (in a depth direction) such that the second waveguide 18 is above the first waveguide 17, or vice versa, for an overlap length, L.sub.o. The first waveguide 17 and the second waveguide 18 are parallel in at least a region where the two waveguides overlap. Light that is guided by the first waveguide 17 from the left to the right will adiabatically couple to the second waveguide 18 such that light that was originally guided at the first depth level will be raised to the second depth level, thus completing a transition between layers of the optical device.
[0101] Referring to FIG. 11, a waveguide array 130 include multiple waveguide cores 131-134 and multiple grating antennas 135-138 associated with a respective waveguide core. The waveguide cores 131-132 have a first width, w.sub.1, and therefore have a first propagation constant. The waveguide cores 133-134 have a second width, w.sub.2, and therefore have a second propagation constant. Therefore, adjacent waveguides have different propagation constants. The grating antennas 135-138 are formed in a perturbation layer that is above the waveguide layer in which the waveguide cores 131-134 are formed. The grating antennas 135-136 include multiple emitter elements spaced with a first grating period, Λ.sub.1, and each emitter element having a first length, first width and first depth. The grating antennas 137-138 include multiple emitter elements spaced with a second grating period, Λ.sub.2, greater than the first grating period, and each emitter element having a second length, second width and second depth.
[0108] Referring to FIG. 14, a waveguide core 150 is located in a waveguide layer that is at a first depth level and a grating antenna 152 is located in a perturbation layer that is at a second depth level different from the first depth level. The perturbation layer is above the waveguide layer and includes a first emitter layer 154 and a second emitter layer 156. Each of the emitter layer 154 and 156 includes multiple emitter elements that form the grating antenna 146. Neither emitter layer is in in physical contact with the waveguide core 150. The first emitter layer 154 is separated from the waveguide core 150 by a gap distance, d.sub.g. The second emitter layer is separated from the first emitter layer by a separation distance, d.sub.s.
[0109] Each emitter element of the first emitter layer 154 have a first length in a longitudinal direction along the length of the waveguide core 150 and each emitter element of the second emitter layer 156 have a second length in the longitudinal direction. The lengths of the emitters in each emitter layer may be different. For example, as illustrated, the emitter element length of the first emitter layer 154 is greater than the emitter element length of the second emitter layer 156. However, the emitter element length of the first emitter layer 154 may also be less than or equal to the emitter element length of the second emitter layer 156.
[0110] The first emitter layer 154 has a first thickness, h.sub.1, in the depth direction and the second emitter layer 156 has a second thickness, h.sub.2, in the depth direction. The second thickness, h.sub.2, may be greater than the first thickness, h.sub.1, to ensure that the second emitter layer 156 perturbs the light guided by the waveguide with the same strength as the first emitter layer 154. This is due to the intensity of the light guided by the waveguide decreasing as a function of distance from the waveguide core 150. Other techniques for ensuring the perturbation of the two emitter layers are approximately equal may also be used. For example, instead of forming the first emitter layer 154 and the second layer 156 from the same material, as illustrated in FIG. 14, the emitter elements of the first emitter layer 154 may be formed from a different material than the emitter elements of the second emitter layer 156. For example, if the emitter elements of the second emitter layer 156 are formed from a material with a larger dielectric constant than a material used to form the emitter elements of the first emitter layer 154, then the thickness in the depth direction of the two emitter layers may be approximately equal.
[0111] The direction light is emitted by the grating antenna 152 can be tuned by setting the gap distance, d.sub.g, the separation distance, d.sub.s, and also an offset distance, d.sub.g, which is a distance that the center of the emitter elements of the second emitter layer 156 are offset relative to the center of the emitter elements of the first emitter layer 154. For example, to tune the emission direction to be vertical in the upward direction, the offset distance, d.sub.o, is approximately ±λ.sub.eff/4+mλ/2, wherein λ.sub.eff is an effective wavelength of light guided by the waveguide and m is an integer, and the separation distance, d.sub.s, is approximately λ.sub.c/4+nλ.sub.c/2, wherein n is an integer and λ.sub.c is an effective wavelength of light in the cladding volume. Other angles of emission can be achieved by setting the offset distance, d.sub.o, and the separation distance, d.sub.s, to different values. For example, as shown in FIG. 12, the first offset distance, d.sub.o, is positive, meaning the light traveling from left to right through the waveguide first encounters the first emitter layer 154, not the second emitter layer 156. This results in the majority of the light being emitted in an upward vertical direction. If the offset distance, d.sub.o, is instead set to be negative, meaning the light traveling from left to right through the waveguide first encounters the second emitter layer 156, not the first emitter layer 154, then the majority of the light emitted by the grating antenna 152 is emitted in a downward vertical direction.
[0112] The emitter elements of any grating antenna used in example optical devices may be formed from various materials. For example, silicon, silicon nitride, poly/amorphous silicon, liquid crystals, aluminum nitride, indium titanium oxide, metals, or germanium may be used to form emitter elements. In some embodiments, a material used to form a grating antenna above a waveguide core may have a higher index of refraction than a material from which the waveguide core is formed. Additionally, as discussed above, if a perturbation layer of a grating antenna includes multiple emitter layers, then each emitter layer may be formed from different materials. For example, a first emitter layer that is nearer to a waveguide core than a second emitter layer may be formed from a material with an index of refraction that is less than the index of refraction of a material used to form the second emitter layer.
[0113] To change the emission rate along the waveguide core 150, the gap distance, d.sub.s, between the waveguide layer and the first emitter layer can be changed. Changing this distance is independent of the profile of the layers themselves so new lithography masks do not have to be fabricated to change the emission rate of the antenna from wafer to wafer. Furthermore, changing the gap distance, d.sub.s, does not change the directionality of the emission because the directionality is determined by the horizontal and vertical offset of the emitter layers 154 and 156. Changing the gap distance, d.sub.s, allows for a robust and inexpensive way to tune the emission of light from an optical device.
Further regarding claim 1, Popovic discloses in figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text, embodiments of multi-layer grating for which scattering element shapes, grating distributions of scattering elements, and differences between adjacent gratings’ scattering elements shapes and distributions act in concert to determine the direction and intensity of light. Popovic, abstract (“An optical coupler has a waveguide coupled to a grating of multiple scattering units, each scattering unit having a first scattering element formed of a shape in a polysilicon gate layer and a second scattering element formed of a shape in a body silicon layer of a metal-oxide-semiconductor (MOS) integrated circuit (IC). The couplers may be used in a system having a coupler on each of a first and second IC, infrared light being formed into a beam passing between the couplers. Vias may be interposed in third ICs between the first and second ICs. The couplers may be configured with nonuniform width of scattering elements to produce Gaussian or focused beams.”).
Popovic – Figures 4-7
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Popovic – Figures 8 and 9
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Popovic – Figures 12 and 13
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Popovic – Selected Text
[0020] FIG. 4 illustrates how constructive interference in a two-element scattering unit can direct power up, and destructive interference ensure that little or none is radiated down.
[0021] FIG. 5 illustrates scatterers formed of polysilicon gates and crystalline silicon shapes defined by oxide isolation on either side of a waveguide formed in the transistor body layer of an SOI process.
[0022] FIG. 6 illustrates a coupler in cross section.
[0024] FIG. 8A illustrates a simulated radiation pattern, using a decibel scale on a radial axis indicating substantially upward directivity for an embodiment configured as a vertical coupler in the upwards direction, and FIG. 8B illustrates a simulated radiation pattern with a decibel scale on radial axis indicating substantially downward directivity for an embodiment configured as a vertical coupler in the downwards direction.
[0025] FIG. 9A illustrates simulated upwards power versus position along a coupler for an embodiment configured as a vertical coupler in the upwards direction, and FIG. 9B illustrates simulated downward power versus position along a coupler for an embodiment configured as a vertical coupler in the downwards direction.
[0030] FIG. 12 illustrates simulated or measured power and angles.
[0031] FIG. 13 illustrates grating parameters such as top width, bottom width, and spacing.
[0072] FIG. 9A illustrates simulated upwards power versus position along a coupler for an embodiment configured as a vertical coupler in the upwards direction, and FIG. 9B illustrates simulated downward power versus position for an embodiment configured as a vertical coupler in the downwards direction. A grating configured for up radiation direction at .lamda.=1550 nm has P.sub.up=96% radiated power in the up direction, P.sub.down=3% radiated power in the down direction, and reflected and transmitted guided powers are both 0.5%. It has the most efficient coupling to a Gaussian beam mode, at a wavelength of 1550 nm, of 76.78%. This is compatible with a fiber having a large mode with MFD=38.73 .mu.m in the longitudinal direction along the grating, at an off-normal angle .theta..sub.up=12.6.degree.. FIG. 8A depicts an example radiation pattern in the x-y plane, in dB scale, with an upward beam at, an off-normal angle of 12.6.degree..
[0073] A grating configured for down radiation direction at .lamda.=1550 nm has P.sub.down=98% radiated power in the down direction (FIG. 8B), P.sub.up=2% radiated power in up direction, and reflected and transmitted guided powers are both near 0%. It has the most efficient coupling at .lamda.=1550 nm of 83% with a Gaussian beam or a fiber mode with field diameter along the grating propagation axis of MFD=21.37 .mu.m and inclined at an off-normal angle .theta..sub.down=10.4.degree.(See FIG. 9B).
Consequently, in light of Popovic’s scattering element embodiments’ predictable beam shaping and steering capabilities, it would have been obvious to one of ordinary skill in the art to modify Watts’ optical antenna embodiments to disclose: a waveguide configured to propagate light; when a direction in which the waveguide extends is defined as a first direction, a direction perpendicular to the first direction is defined as a second direction, and a direction perpendicular to both the first direction and the second direction is defined as a third direction, a first diffraction grating group having a plurality of first diffraction gratings arranged at a predetermined period in the first direction on both sides of the waveguide in the second direction, and a second diffraction grating group having a plurality of second diffraction gratings arranged at a same period as the first diffraction grating in the first direction on both sides of the waveguide in the second direction, wherein the first diffraction grating and the second diffraction grating have different centroid positions in the first direction and the third direction, and the second diffraction grating is located closer to the waveguide than the first diffraction grating in the second direction; Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text; because the resulting configurations would facilitate designing, fabricating, and deploying light emitting optical devices that predictably and efficiently steer optical beams. Watts, paragraphs [0062] (“The inventors have recognized that there is a need for a light emitting optical device that is allows unidirectional emission of light in a controllable direction and is robust to variations that commonly occur during fabrication, such as proximity and rounding effects that can alter the physical geometry of a device in an unpredictable way when compared to a desired geometry. For example, some implementations of an optical device may include antennas that are distinct from the waveguides. The antennas may include multiple emitter elements that may, for example, be separated from the waveguides by a gap. By separating the guiding and emitting function of a perturbation layer of the optical device the emitter elements can cause light guided by the waveguides to be emitted without using emitter elements formed directly in the waveguide using partial or full etching. Instead, the emitter elements can be formed in a separate perturbation layer using full etching. By reducing the use of directly etching the waveguide in forming the optical device, the rounding and proximity effects are restricted to regions that are far from the optical mode of the light guided by the waveguides.”) and [0063] (“The inventors have also recognized and appreciated that using a single layer of emitter elements (a “single emitting layer”) that is separate from the layer of waveguides (“the waveguide layer”), up to 50% of the optical power may be lost due to light emission occurring in both an upward and downward direction. By including multiple emitting layers, the amount of optical power emitted in the desired direction can be increased to greater than 90%, and in some cases higher than 99%.”).
Regarding claims 2-10, as dependent upon claim 1, it would have been obvious to one of ordinary skill in the art to modify Watts in view of Popovic’s optical antenna embodiments, as applied in the rejection of claim 1, to disclose:
2. The optical antenna according to claim 1, wherein the waveguide, the first diffraction grating, and the second diffraction grating are composed of parts of a plurality of films laminated on a substrate, the first diffraction grating is composed of a film on a same layer as the waveguide, and the second diffraction grating is formed of a film in a layer different from that of the waveguide. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
3. The optical antenna according to claim 1, wherein a center of gravity of the second diffraction grating is located above the waveguide in the third direction. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
4. The optical antenna according to claim 1, wherein the waveguide, the first diffraction grating, and the second diffraction grating are spaced apart from each other. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
5. The optical antenna according to claim 1, wherein the second diffraction grating is made of a material having a lower refractive index than the waveguide and the first diffraction grating. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
6. The optical antenna according to claim 5, wherein the waveguide and the first diffraction grating are made of silicon, and the second diffraction grating is made of silicon nitride. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
7. The optical antenna according to claim 1, wherein the first diffraction grating arranged on one side of the second direction with respect to the waveguide is defined as a first one side diffraction grating, the first diffraction grating arranged on the other side of the second direction with respect to the waveguide is defined as a first other side diffraction grating, the second diffraction grating arranged on one side of the second direction with respect to the waveguide is defined as a second one side diffraction grating, the second diffraction grating disposed on the other side of the second direction with respect to the waveguide is defined as a second other side diffraction grating, the plurality of first other side diffraction gratings are arranged offset in the first direction with respect to the plurality of first one-side diffraction gratings, the plurality of second other side diffraction gratings are arranged offset in the first direction with respect to the plurality of second one-side diffraction gratings, and an offset amount of the first other side diffraction grating with respect to the first one side diffraction grating is equal to the offset amount of the second other side diffraction grating with respect to the second one side diffraction grating. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
8. The optical antenna according to claim 7, wherein the offset amount of the first other side diffraction grating with respect to the first one side diffraction grating and the offset amount of the second other side diffraction grating with respect to the second one side diffraction grating are set to half the period of the first diffraction grating and the second diffraction grating in the first direction. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
9. An optical antenna array, comprising: a plurality of optical antennas according to claim 1. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
10. The optical antenna array according to claim 9, wherein at least two of the plurality of optical antennas share the first diffraction grating. Popovic, figures 4-9 and 12-13, and related figures and text, for example, Popovic – Selected Text; Watts, figures 2, 3, 4, 5, 11 and 14, and related figures and text, for example, Watts – Selected Text.
because the resulting configurations would facilitate designing, fabricating, and deploying light emitting optical devices that predictably and efficiently steer optical beams. Watts, paragraphs [0062] and [0063].
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER RADKOWSKI whose telephone number is (571)270-1613. The examiner can normally be reached on M-Th 9-5. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Thomas Hollweg, can be reached on (571) 270-1739. The fax phone number for the organization where this application or proceeding is assigned is (571) 273-8300.
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/PETER RADKOWSKI/Primary Examiner, Art Unit 2874