DETAILED 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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement filed 08/19/2025 fails to comply with the provisions of 37 CFR 1.98(a)(4) because it lacks the appropriate size fee assertion. It has been placed in the application file, but the information referred to therein has not been considered as to the merits.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 15-18 and 23 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 15, the final line of the claim refers to “the steering unit”. However, a plurality of steering units have now been recited leading to confusion as to which specific steering unit “the steering unit” refers to. Dependent claims 16-18 do not cure claim 15 of this issue, and are similarly rejected.
Further regarding claim 17, the claim recites “a polarisation dependent redirector, preferably a polarisation dependent diffraction grating”. (emphasis added) However, when looking to the Specification, it is unclear if “preferably” limits this element (i.e. is it optionally a grating or must be a grating). Therefore, one of ordinary skill in the art would find the meets and bounds of the claim to be unclear. Dependent claim 18 does not cure claim 17 of this issue and is similarly rejected.
Claim 23 recites the limitation "the selected optical redirection for the first polarisation adjuster". There is insufficient antecedent basis for this limitation in the claim. For the purposes of prior art rejections, the claim will be taken to depend on claim 22 which first recites this limitation.
Claim Rejections - 35 USC § 102
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 (i.e., changing from AIA to pre-AIA ) 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.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1, 2, 4, 5, 7, 12, 15, 19, and 20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Birnbaum et al, U.S. Patent No. 10,298,325.
Regarding claim 1, Birnbaum teaches a free space optical communications system (see Birnbaum Figure 1), comprising:
a first module and a second module (see Figure 1, laser terminals 105 and 110), the first module being configured to transmit modulated light to the second module (see Figure 1, transmit light beam 120 and column 1, “A bidirectional laser communication system (e.g., in space settings) can include two or more laser terminals (e.g., either stationary or non-stationary terminals) that communicate between each other by encoding information into light beams” which implies modulation), wherein:
the first module comprises a first-module transmitter (see Figure 2A, which is an embodiment of laser terminals 105 and 110, optical transceiver 205 with transceiver fiber 227, which implies a transmitter) and a first-module steerer; the first-module transmitter is configured to transmit light out of the first module via the first-module steerer (see Figure 2A, optical beam coupling device 225 outputting beam 215 and column 4, “The optical beam coupling device 225 is a single optical assembly used by both the receive light beam 210 and the transmit light beam 215 to induce a specific steering angle 220 (i.e., point-ahead angle) between the receive light beam 210 and the transmit light beam 215”);
the first-module steerer is configured to redirect light received from the first-module transmitter towards the second module based on a first control signal (see Figure 2A, controller 229 and column 4, “The controller 229 may control a position of the at least one optical element of the optical beam coupling device 225 to achieve a specific steering angle 220 between the receive light beam 210 and the transmit light beams 215”), the first-module steerer comprising: a first polarisation adjuster (see Figure 4, which is an embodiment of optical beam coupling device 225 of Figure 2A, quarter waveplate 405 and column 9, “The quarter-waveplate 405 may convert the transmit light beam 425 entering the optical beam coupling device 400 from circularly polarized light of the first handedness into linearly polarized light of a first polarization (e.g., polarized along x dimension)”) configured to change a polarisation of the received light based on the first control signal (see column 11, “The optical transceiver controls (e.g., via the controller) positions of a pair of waveplates to adjust the steering angle to the determined steering angle, each waveplate in the pair positioned adjacent to a different one of the plurality of optical elements”); and a first polarisation dependent redirector configured to selectively redirect light received from the first polarisation adjuster along one or more of a plurality of available directions as a function of the polarisation of the light (see Figure 4, compound prism 415 and column 9, “The compound prism 415 may include a pair of wedges 407, 409 implemented using birefringent materials for steering linearly polarized incident light by a specific angle depending on a direction of linear polarization of the incident light”);
the second module comprises a second-module steerer and a second-module detector (see Figures 2A and 4 as applied to the laser terminal 110 of Figure 1. As with a transmitter, a transceiver fiber 227 implies a detector);
the second-module steerer is configured to redirect light received from the first module (see Figure 4, receive light beam 430) towards the second-module detector based on a second control signal (see column 4, “The controller 229 may control a position of the at least one optical element of the optical beam coupling device 225 to achieve a specific steering angle 220 between the receive light beam 210 and the transmit light beams 215”), the second- module steerer comprising: a second polarisation adjuster configured to change a polarisation of the received light signal (see Figure 4, quarter-waveplate 410 and column 9, “Similarly, the quarter-waveplate 410 may convert the receive light beam 430 entering the optical beam coupling device 400 from circularly polarized light of the second handedness into linearly polarized light of a second polarization orthogonal to the first polarization (e.g., polarized along y dimension)”) based on the second control signal (see column 11, “The optical transceiver controls (e.g., via the controller) positions of a pair of waveplates to adjust the steering angle to the determined steering angle, each waveplate in the pair positioned adjacent to a different one of the plurality of optical elements”); and a second polarisation dependent redirector configured to selectively redirect light received from the second polarisation adjuster along one or more of a plurality of available directions as a function of the polarisation of the light (see Figure 4, compound prism 420 and column 10, “In general, the compound prisms 415 and 420 are made of birefringent materials that deflect (steer) the transmit light beam 425 and the receive light beam 430 though different angles”); and
the second-module detector is configured to detect light from the first module (this is implied by the transceiver of Figure 2A).
Regarding claim 2, Birnbaum teaches all the limitations of claim 1, and further teaches wherein the first and second control signals represent relative positions of the first and second modules (see Birnbaum column 3, “The laser terminal 105 needs to account for changing of relative positions between the laser terminal 105 and the laser terminal 110 when sending a light beam to the laser terminal 110. Thus, the laser terminal 110 outputs a transmit light beam 120 toward a future relative position of the laser terminal 110, i.e., the laser terminal 105 steers the transmit light beam 120 from the receive light beam 115 by a certain differential (point-ahead) angle 125”).
Regarding claim 4, Birnbaum teaches all the limitations of claim 1, and further teaches wherein the first module further comprises a first-module detector configured to detect light from the second module to allow bidirectional communication between the first and second modules (this is implied by the transceiver of Birnbaum Figure 2A, as applied to laser terminal 105 of Figure 1).
Regarding claim 5, Birnbaum teaches all the limitations of claim 4, and further teaches wherein the first-module steerer is configured to redirect light received from the second module towards the first-module detector along equal and opposite directions as compared to the redirection by the first-module steerer of light received from the first-module transmitter towards the second module (see Birnbaum Figure 4, paths taken by receive light beam 430 and transmit light beam 425).
Regarding claim 7, Birnbaum teaches all the limitations of claim 4, and further teaches wherein the first-module steerer is configured to redirect light received from the second module towards the first-module detector by passing the light through a further polarisation adjuster and the first polarisation dependent redirector (see Birnbaum Figure 4, compound prism 420 and quarter-waveplate 410 as applied to laser terminal 105 of Figure 1).
Regarding claim 12, Birnbaum teaches all the limitations of claim 1, and further teaches wherein either or each of the first polarisation adjuster and the second polarisation adjuster comprises a liquid crystal cell, optionally a nematic liquid crystal cell (see Birnbaum column 9, “Quarter-waveplates can be made of birefringent materials such as quartz, organic material sheets, or liquid crystal”).
Regarding claim 15, Birnbaum teaches all the limitations of claim 1, and further teaches wherein either or each of the first-module steerer and the second-module steerer comprises:
a plurality of steering units arranged to guide propagation of light through the steering units in series, wherein each of the steering units is capable of redirecting light selectively along any of a plurality of predetermined directions relative to the steering unit (see Birnbaum Figure 4 as applied to both laser terminals 105 and 110 of Figure 1. The combination of elements 405 and 415 is one steering unit and 420 and 410 is another steering unit).
Regarding claim 19, Birnbaum teaches a method of performing free space optical communication between a first module and a second module (see Birnbaum Figure 1, laser terminals 105 and 110), the method comprising:
generating light for transmission from the first module to the second module (see Figure 2A, which is an embodiment of laser terminals 105 and 110, transmit light beam 215);
controlling a first polarisation adjuster (see Figure 4, which is an embodiment of optical beam coupling device 225 of Figure 2A, quarter waveplate 405 and column 9, “The quarter-waveplate 405 may convert the transmit light beam 425 entering the optical beam coupling device 400 from circularly polarized light of the first handedness into linearly polarized light of a first polarization (e.g., polarized along x dimension)”) to change a polarisation of the generated light see column 11, “The optical transceiver controls (e.g., via the controller) positions of a pair of waveplates to adjust the steering angle to the determined steering angle, each waveplate in the pair positioned adjacent to a different one of the plurality of optical elements”) and using a first polarisation dependent redirector to selectively redirect light received from the first polarisation adjuster along one or more of a plurality of available directions as a function of the polarisation of the light (see Figure 4, compound prism 415 and column 9, “The compound prism 415 may include a pair of wedges 407, 409 implemented using birefringent materials for steering linearly polarized incident light by a specific angle depending on a direction of linear polarization of the incident light”); and
redirecting light received from the first module at the second module (see Figure 2A, receiver light beam 210 and Figure 4, receive light beam 430 as applied to laser terminal 110 of Figure 1) towards a second-module detector (this is implied by the transceiver of Figure 2A).
Regarding claim 20, Birnbaum teaches all the limitations of claim 19, and further teaches wherein the redirection of light received from the first module is performed by controlling a second polarisation adjuster to change a polarisation of the received light in such a way (see Birnbaum Figure 4, as applied to laser terminal 110 of Figure 1, quarter-waveplate 410 and column 9, “Similarly, the quarter-waveplate 410 may convert the receive light beam 430 entering the optical beam coupling device 400 from circularly polarized light of the second handedness into linearly polarized light of a second polarization orthogonal to the first polarization (e.g., polarized along y dimension)”) that a second polarisation dependent redirector receiving the light redirects the light into a selected one of a plurality of available directions (see Birnbaum Figure 4, quarter-waveplate 410 and column 9, “Similarly, the quarter-waveplate 410 may convert the receive light beam 430 entering the optical beam coupling device 400 from circularly polarized light of the second handedness into linearly polarized light of a second polarization orthogonal to the first polarization (e.g., polarized along y dimension)”) that is most closely aligned with the second-module detector (this is implied by Birnbaum column 4, “The optical transceiver 205 is configured to in-couple the receive light beam 210 transmitted from another laser terminal (not shown in FIG. 2A)”).
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, 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.
Claim(s) 6, 13, and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Birnbaum et al, U.S. Patent No. 10,298,325.
Regarding claim 6, Birnbaum teaches all the limitations of claim 5, but does not expressively teach wherein the first-module steerer is large enough to allow the first-module detector and the first-module transmitter to be positioned adjacent to each other.
However, one of ordinary skill in the art before the effective filing date of the invention would have found it obvious as a matter of design choice to select a first-module steerer to be the claimed size based on system requirements and available space in the first module.
Regarding claim 13, Birnbaum teaches all the limitations of claim 12, but does not expressively teach wherein the liquid crystal cell is operable to switch between a plurality of different states in response respectively to the first control signal or the second control signal, the plurality of different states comprising at least: a half- wave plate state in which the cell has the properties of a half-wave plate.
However, Birnbaum in a separate embodiment teaches a polarization adjuster comprising a liquid crystal cell wherein the liquid crystal cell is operable to switch between a plurality of different states in response respectively a control signal, the plurality of different states comprising at least: a half- wave plate state in which the cell has the properties of a half-wave plate (see Birnbaum column 10, “In some embodiments (not shown in FIG. 4), instead of the quarter-waveplates 405, 410, the optical beam coupling device 400 includes a pair of half-waveplates, i.e., the quarter-waveplate 405 is replaced by a first half-waveplate and the quarter-waveplate 410 is replaced by a second half-waveplate. A half-waveplate is an optical element that shifts polarization of incident light. A half-waveplate includes a polarization axis and the half-waveplate shifts the polarization axis 90 degrees relative to incident polarized light. Half-waveplates can be made of birefringent materials such as quartz, organic material sheets, or liquid crystal”); and a full-wave plate state in which the cell has the properties of a full-wave plate.
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious as a matter of simple substitution to replace the quarter-waveplates of Birnbaum Figure 4 with half-waveplates taught in a separate embodiment of Birnbaum to yield the predictable results of successfully altering the polarization state of input and output light.
Regarding claim 14, Birnbaum teaches all the limitations of claim 1, but does not expressively teach wherein either or each of the first polarisation dependent redirector and the second polarisation dependent redirector comprises a polarisation dependent diffraction grating.
However, Birnbaum in a separate embodiment teaches a polarization dependent redirector comprising a polarisation dependent diffraction grating (see Birnbaum column 10, “Alternatively, instead of using the compound prisms 415, 420 made of wedges, the optical beam coupling device 400 can be implemented using compound optical elements based on Bragg polarization gratings. Thus, referring back to FIG. 2B, each of the first and second optical elements 230, 235 may be implemented using a pair of Bragg polarization gratings”).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious as a matter of simple substitution to replace the compound prisms of Birnbaum Figure 4 with gratings taught in a separate embodiment of Birnbaum to yield the predictable results of successfully steering the light.
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Birnbaum et al, U.S. Patent No. 10,298,325 in view of Mitchell et al, U.S. Patent No. 11,005,565.
Regarding claim 3, Birnbaum teaches all the limitations of claim 1, but does not expressively teach wherein either or each of the first module and the second module comprises a light spreader, preferably optionally a diffuser, configured to spread light from a radiation source such that any image of the radiation source formed outside of the first module and the second module is larger than the image would be without the light spreader.
However, Mitchell in a similar invention in the same field of endeavor teaches a free space optical communication system comprising a first and second module (see Mithcell Figure 1B, terminals 100) each comprising steerer (see Figure 2A, which is an embodiment of terminals 100, beam steering unit 205) as taught in Birnbaum wherein
either or each of the first module and the second module comprises a light spreader, preferably optionally a diffuser, configured to spread light from a radiation source such that any image of the radiation source formed outside of the first module and the second module is larger than the image would be without the light spreader (see Figure 2A, telescope 200 coupled to Tx Source 225 and column 4, “The telescope 200 may be as simple as a single lens or it may include additional optical components, such as diffusers, phase screens, beam expanders, mirrors, and lenses”).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to combine the teaching of a light spreader to spread the light as taught in Mitchell with the system taught in Birnbaum, the motivation being to more easily allow the beams to be detected via the spread of the signal.
Claim(s) 8, 10, 11, and 21-23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Birnbaum et al, U.S. Patent No. 10,298,325 in view of Wirth et al, U.S. Publication No. 2006/0024061.
Regarding claim 8, Birnbaum teaches all the limitations of claim 4, but does not expressively teach wherein the first module and the second module are configured to perform a localization procedure comprising: the first module sending a first localization signal as transmitted light to the second module; and the second module using the second-module steerer to sequentially apply a plurality of different redirections to light received from the first module and to select as an optimal redirection for the second-module steerer the redirection that provides a strongest signal at the second-module detector.
However, Wirth in a similar invention in the same field of endeavor teaches a free space optical communications system with a first module and a second module (see Wirth Figure 3B, terminals 2A and 2B) comprising a first module steerer and a second module steerer, respectively to steer a light signal to a second-module detector (see Figure 3B, fast steering mirror connected to laser in terminal 2A and fast steering mirror connected to the detector in terminal 2B) as taught in Birnbaum wherein the first module and the second module are configured to perform a localization procedure comprising:
the first module sending a first localization signal as transmitted light to the second module (see Figure 3B, beacon beam from xmit aperture of terminal 2A to receiver aperture of terminal 2B); and
the second module using the second-module steerer to sequentially apply a plurality of different redirections to light received from the first module and to select as an optimal redirection for the second-module steerer the redirection that provides a strongest signal at the second-module detector (see paragraph [0092] referring to a Laser Beam Pointing Mechanism which paragraph [0097] specifies involves the fast steering mirror terminal 2B).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to combine the teaching of adjusting a steerer to maximize power as taught in Wirth with the system taught in Birnbaum, the motivation being to ensure proper alignment between the modules thereby increasing data throughput.
Regarding claim 10, Birnbaum in view of Wirth teaches all the limitations of claim 8, and further teaches wherein the localization procedure further comprises:
the second module sending a second localization signal as transmitted light to the first module (see Wirth Figure 3B, beacon beam from xmit aperture of terminal 2B to receiver aperture 2A), optionally using the selected optimal redirection for the second-module steerer; and
the first module using the first-module steerer to sequentially apply a plurality of different redirections to light received from the second module and to select as an optimal redirection for the first-module steerer the redirection that provides a strongest signal at the first-module detector (see Wirth Figure 3B, fast steering mirror of terminal 2A to detector and paragraph [0092]).
Regarding claim 11, Birnbaum in view of Wirth teaches all the limitations of claim 10, and further teaches wherein the first module and the second module are configured to perform bidirectional communication after completion of the localization procedure while:
controlling the first-module steerer to redirect light based on the selected optimal redirection for the first-module steerer; and/or controlling the second-module steerer to redirect light based on the selected optimal redirection for the second-module steerer (see Wirth paragraph [0092]).
Regarding claim 21, Birnbaum teaches all the limitations of claim 19, but does not expressively teach performing a localization procedure, the localization procedure comprising: sending a first localization signal as transmitted light, optionally in a wide angle transmission mode, from the first module to the second module; and controlling the second polarisation adjuster to sequentially apply a plurality of different redirections to light received from the first module and to select as an optimal redirection for the second polarisation adjuster the redirection that provides a strongest signal at the second-module detector.
However, Wirth in a similar invention in the same field of endeavor teaches a free space optical communications method with a first module and a second module (see Wirth Figure 3B, terminals 2A and 2B) comprising a first module steerer and a second module steerer, respectively to steer a light signal to a second-module detector (see Figure 3B, fast steering mirror connected to laser in terminal 2A and fast steering mirror connected to the detector in terminal 2B) as taught in Birnbaum, the method comprising
performing a localization procedure, the localization procedure comprising:
sending a first localization signal as transmitted light, optionally in a wide angle transmission mode, from the first module to the second module (see Figure 3B, beacon beam from xmit aperture of terminal 2A to receiver aperture of terminal 2B); and
controlling the second module steerer to sequentially apply a plurality of different redirections to light received from the first module and to select as an optimal redirection for the second module steerer the redirection that provides a strongest signal at the second-module detector (see paragraph [0092] referring to a Laser Beam Pointing Mechanism which paragraph [0097] specifies involves the fast steering mirror terminal 2B).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to combine the teaching of adjusting a steerer to maximize power as taught in Wirth with the method of using a polarization adjuster in a beam steerer as taught in Birnbaum, the motivation being to ensure proper alignment between the modules thereby increasing data throughput.
Regarding claim 22, Birnbaum in view of Wirth teaches all the limitations of claim 21, and further teaches wherein the localization procedure further comprises:
sending a second localization signal as transmitted light from the second module to the first module (see Wirth Figure 3B, beacon beam from xmit aperture of terminal 2B to receiver aperture 2A); and
controlling the first polarisation adjuster to sequentially apply a plurality of different redirections to light received from the second module and to select as an optimal redirection for the first polarisation adjuster the redirection that provides a strongest signal at a first- module detector (see Wirth Figure 3B, fast steering mirror of terminal 2A to detector and paragraph [0092] as combined with Birnbaum Figure 2A).
Regarding claim 23, Birnbaum in view of Wirth teaches all the limitations of claim [22], and further teaches
performing bidirectional communication after completion of the localization procedure while:
controlling the first polarisation adjuster to redirect light based on the selected optimal redirection for the first polarisation adjuster; and/or controlling the second polarisation adjuster to redirect light based on the selected optimal redirection for the second polarisation adjuster (see Wirth paragraph [0092] as combined with Birnbaum Figure 4).
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Birnbaum et al, U.S. Patent No. 10,298,325 in view of Wirth et al, U.S. Publication No. 2006/0024061 and Cunningham et al, U.S. Publication No. 2007/0031151.
Regarding claim 9, Birnbaum in view of Wirth teaches all the limitations of claim 8, but does not expressively teach wherein: the first module comprises a beam divergence adjuster configured to allow the first module to be selectively operable in a wide angle transmission mode in which the first module transmits light into a wide solid angle and a narrow angle transmission mode in which the first module transmits light into a narrower solid angle; and the first module is configured to send the first localization signal in the wide angle transmission mode.
However, Cunningham in a similar invention in the same field of endeavor teaches a free space optical communication system comprising a first module (see Cunningham Figure 1) configured to transmit a first localization signal (see Figure 1, beacon transmit signal 138 and Figure 2, step 208) as taught in Birnbaum in view of Wirth wherein:
the first module comprises a beam divergence adjuster configured to allow the first module to be selectively operable in a wide angle transmission mode in which the first module transmits light into a wide solid angle and a narrow angle transmission mode in which the first module transmits light into a narrower solid angle; and the first module is configured to send the first localization signal in the wide angle transmission mode (see Figure 1, switch 142 and paragraphs [0029]-[0030]).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to combine the teaching of allowing for wide and narrow beam signals as taught in Cunningham with the system taught in Birnbaum in view of Wirth, the motivation being allow the modules to quickly locate each other initially via such wider initial beams.
Claim(s) 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Birnbaum et al, U.S. Patent No. 10,298,325 in view of Escuti et al, U.S. Patent No. 8,982,313.
Regarding claim 16, Birnbaum teaches all the limitations of claim 15, but does not expressively teach wherein the plurality of predetermined directions for one of the steering units lie in a first plane and the plurality of predetermined directions for a different one of the steering units lie in a second plane, and the first plane is non-parallel with the second plane.
However, Escuti in a similar invention in the same field of endeavor teaches a system with a plurality of steering units for optical beams (see Escuti Figure 1A, rotatable polarization gratings 101 and 102 and column 6, “FIGS. 1A and 1B are perspective views illustrating mechanical beam steering embodiments of the present invention including two or more stacked and independently rotatable polarization gratings (PGs)”) each configured to steer beams in a plurality of predetermined directions (see Figure 2B which shows parallel gratings, angles of output flight from each) as taught in Birnbaum wherein
the plurality of predetermined directions for one of the steering units lie in a first plane and the plurality of predetermined directions for a different one of the steering units lie in a second plane, and the first plane is non-parallel with the second plane (see Figure 1A, wherein the non parallel grating placement would indicate that the plane that the angles light would travel are not the same for each).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to combine the teaching of having directions for light to travel for different steering units to be in different planes as taught in Escuti with the system taught in Birnbaum, the motivation being to allow more freedom for where to steer light.
Regarding claim 17, Birnbaum teaches all the limitations of claim 15, and further teaches wherein:
each of the steering units comprises:
a polarisation adjuster configured to change a polarisation of light interacting with the polarisation adjuster; and a polarisation dependent redirector, preferably a polarisation dependent diffraction grating, configured to redirect light received from the polarisation adjuster as a function of a polarisation of the light (see Birnbaum Figure 4, one steering unit being quarter waveplate 405 and compound prism 415 and one steering unit being quarter waveplate 410 and compound prism 420).
Birnbaum does not expressively teach the polarisation dependent redirector of one of the steering units is rotated by a rotation angle relative to the polarisation dependent redirector of another one of the steering units.
However, Escuti in a similar invention in the same field of endeavor teaches a system comprising a plurality of steering units (see Escuti Figure 7A, one steering unit with polarization selector 705 and polarization grating 701 and a second steering unit with polarization selector 710 and polarization grating 702) each of the steering units comprises: a polarisation adjuster configured to change a polarisation of light interacting with the polarisation adjuster (see column 2, “The polarization selector may be configured to alter the polarization state of light that passes therethrough, and may be switchable in some embodiments”); and a polarisation dependent redirector, preferably a polarisation dependent diffraction grating, configured to redirect light received from the polarisation adjuster as a function of a polarisation of the light (see column 2, “The first beam steering stage includes a first polarization grating configured to polarize and redirect a polarized input beam incident thereon to output a first beam having a first propagation angle. The second beam steering stage includes a second polarization grating configured to analyze and redirect the first beam incident thereon to output a second beam having a second propagation angle”) as taught in Birnbaum wherein
the polarisation dependent redirector of one of the steering units is rotated by a rotation angle relative to the polarisation dependent redirector of another one of the steering units (see column 2, “At least one of the first polarization grating and the second polarization grating is operable to be independently rotated about an axis to rotate a propagation direction of a corresponding one of the first beam and the second beam”).
One of ordinary skill in the art before the effective filing date of the invention would have found it obvious to combine the teaching of having a polarization dependent redirector to be rotated relative to another polarization dependent redirection as taught in Escuti with the system taught in Birnbaum, the motivation being to allow for dynamic steering adjustments to be made in the system.
Regarding claim 18, Birnbaum in view of Escuti teaches all the limitations of claim 17, but does not expressively teach wherein the rotation angle is 90 degrees. However, one of ordinary skill in the art before the effective filing date of the invention would have found it obvious as a matter of design choice to have the rotation angle be as claimed based on system needs and positioning of the first and second modules.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CASEY L KRETZER whose telephone number is (571)272-5639. The examiner can normally be reached M-F 10:00-7:00 PM Pacific Time.
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/CASEY L KRETZER/Primary Examiner, Art Unit 2635
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