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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 08/04/2025 and 12/01/2025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
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.
Claims 1-4, 7-16, 18 and 20 are rejected under 35 U.S.C. § 103 as being unpatentable over Miller et al. (US 2018/0031744 A1, of record) in view of Greiner et al. (US 8,593,732 B1, of record).
Regarding claim 1, Miller discloses a method of forming a diffracted order (Figure 2; [0024]-[0029] discloses: operating a thin film TIR diffraction grating which receives incident light and diffracts the incident light into a reflected diffraction order), the method comprising:
providing a grating ([0029] discloses: 200, TIR diffraction grating) having a dielectric substrate ([0024] discloses: 205, substrate) characterized by a substrate index of refraction ([0017] discloses: substrate made of fused silica with a refractive index of approximately 1.45-1.49) and comprising:
an incident light surface (Figure 2 depicts: upper surface of 205, substrate through which the incident optical beam is received from 220, optical element/prism) and a second surface (Figure 2 depicts: lower surface of 205, substrate, adjacent to 210, etch-stop layer and 215, grating layer) opposing the incident light surface (Figure 2 depicts: upper and lower surfaces of 205, substrate opposing surfaces);
a dielectric layer ([0024] discloses: 215, thin film grating layer) coupled to the second surface of the dielectric substrate (Figure 2 depicts: 215, thin film grating layer coupled to the bottom surface of the dielectric substate, considered the bottom surface), wherein the dielectric layer is characterized by a layer index of refraction greater than the substrate index of refraction ([0028] discloses: 215, thin film grating layer may comprise, inter alia, silicon or tantala, with indices of refraction of n = 3.60 and n = 2.10, respectively, both greater than the index of refraction of fused silica) and a periodic structure ([0027] discloses: 215, thin film grating, may have a binary grating profile);
directing a light beam to be incident on the incident light surface of the dielectric substrate (Figure 2 depicts: incident light entering 220, optical element and being directed toward 200, thin film diffracting grating/205, substrate);
propagating the light beam through the dielectric layer ([0027]-[0029] discloses: 215, thin film grating layer diffracts the incident light, and that the gating operates by TIR when light is incident beyond the critical angle; thus, during operation, the incident optical field propagates into/through 215, dielectric grating layer to interact with its periodic gating structure);
diffracting the light beam from the periodic structure to form a reflected order ([0027]-[0029] discloses: incident light is totally internally reflected into, inter alia, the ± 1st reflected diffraction order, and expressly identifies 215, grating layer as the reflective dielectric grating layer that diffracts incident light); and
propagating the reflected order through the dielectric layer (Figure 2 depicts: reflected diffraction order generated by 215, grating layer propagates back through the grating-layer region toward 205, substrate).
Miller fails to disclose a method wherein the grating is an immersion grating. Miller and Greiner are related because both disclose periodic gratings.
Greiner teaches an immersion grating (Figure 2 depicts: diffraction grating used as an immersion grating in a total internal reflection arrangement).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Greiner in view of Miller and provide wherein the grating is an immersion grating. Doing so would allow for eliminating transmitted optical pathways and concentrate optical energy into reflected diffraction orders, thereby reducing optical loss and improving diffraction efficiency.
Regarding claim 2, the modified Miller discloses the method of claim 1 further comprising propagating the reflected order through the incident light surface of the dielectric substrate (Grenier: Figure 3 depicts: 302, substate having 303, entrance face, through which the incident optical signal enters the substrate, the incident signal propagates within the substate to 301, immersion grating and is back diffracted as a reflected order; Greiner teaches operation near the Littrow condition, such that the back diffraction reflected order propagates through 303, entrance face, See Col. 4, lines 30-45; Examiner notes that the same motivation to combine applied to an earlier claim, 1, also applies here, and no further analysis is required, consistent with MPEP § 2143, which permits reliance on previously articulated rationale where the combination and reasonings remain unchanged).
Regarding claim 3, the modified Miller discloses the method of claim 1 wherein the reflected order comprises an m=−1 order (Greiner: Col. 4, lines 50-58 teach: only the zeroth and first orders share the energy of the incident optical signal after it interacts with 301, immersion grating; Examiner notes that the same motivation to combine applied to an earlier claim, 1, also applies here, and no further analysis is required, consistent with MPEP § 2143, which permits reliance on previously articulated rationale where the combination and reasonings remain unchanged).
Regarding claim 4, the modified Miller discloses the method of claim 1 wherein the dielectric layer (Figure 2 depicts: 215, grating layer) is characterized by a predetermined thickness D and includes:
a first portion of the dielectric layer having a first thickness d.sub.1; and
a second portion of the dielectric layer have a second thickness d.sub.2, wherein D=d.sub.1+d.sub.2 and the periodic structure is formed in the second portion of the dielectric layer (Figure 2 depicts: 215, grating layer, having a periodic grating formed by etching the layer to produce repeating ridges and grooves; thus, the unetched portions underlying the grooves and the patterned ridge portions correspond to the first and second thicknesses and their sum is equal to both heights; thus D=d.sub.1+d.sub.2).
Regarding claim 7, the modified Miller discloses the method of claim 4 wherein d.sub.2 is between 250 nm and 350 nm ([0043] discloses: grating height of 0.35 microns=350 nm, which falls within the claimed range).
Regarding claim 8, the modified Miller discloses the method of claim 1 wherein the periodic structure comprises a one-dimensional diffraction grating ([0032] discloses: repeating binary ridge and gap patterns per lines/mm, thus considered a one-dimensional diffraction grating).
Regarding claim 9, the modified Miller discloses the method of claim 1 wherein the reflected order is the only diffracted order (Greiner: Col. 3 lines 57-62 teaches: diffracted orders higher than the first diffracted order are absent within the high index medium and no diffraction into the low medium; thus the reflected order is the only diffracted order as under these conditions the only remaining diffracted order is the first reflected diffracted order; the other remaining pathway is merely the reflected zeroth order/specular reflection, which is not considered a diffracted order).
Regarding claim 10, the modified Miller discloses the method of claim 1 wherein the dielectric layer comprises at least one of tantalum pentoxide, hafnium oxide, scandium oxide, or titania oxide ([0028] discloses: 215, grating layer, made of, inter alia, tantala: Ta.sub.2O.sub.5, which is tantalum pentoxide).
Regarding claim 11, the modified Miller discloses the method of claim 1 wherein the dielectric substrate comprises fused silica ([0017] discloses: substrate made of fused silica).
Regarding claim 12, the modified Miller discloses the method of claim 1 wherein the layer index of refraction is greater than or equal to 1.9 and less than or equal to 2.2 over a wavelength range from 1030 nm to 1080 nm ([0028] discloses: 215, thin film grating layer, may be tantala; Examiner notes that by material property, tantala has a refractive index of 2.07 between 1030 and 1080 nm, which falls within the claimed range).
Regarding claim 13, the modified Miller discloses the method of claim 1 wherein the periodic structure has a period of at least 2,000 lines/mm (Greiner: Col. 6 lines 26-27 teach: grating period of 3200 lines/mm; Examiner notes that the same motivation to combine applied to an earlier claim, 1, also applies here, and no further analysis is required, consistent with MPEP § 2143, which permits reliance on previously articulated rationale where the combination and reasonings remain unchanged).
Regarding claim 14, the modified Miller discloses the method of claim 1 wherein the periodic structure comprises a binary grating profile, a sinusoidal grating profile, a trapezoidal grating profile, a sawtooth grating profile, a multilevel grating profile, or a blazed grating profile ([0016] discloses: binary grating profile).
Regarding claim 15, the modified Miller discloses the method of claim 1 wherein the periodic structure is characterized by a duty cycle between 0.20 and 0.35 ([0038] discloses: a normalized grooved width of 0.4 and a grating height of 0.88 microns, the duty cycle is calculated to be 0.24, which falls within the claimed range).
Regarding claim 16, the modified Miller discloses the method of claim 1 further comprising a second dielectric layer coupled to the dielectric layer and having an index of refraction greater than the substrate index of refraction ([0028] discloses: 215, grating layer, may be formed from a dielectric layer that includes a small number, one or two, layers of dielectric material; made of, inter alia, tantala n=2.10, which is greater than the index of refraction of the substrate index of refraction of fused silica n=1.45-1.49).
Regarding claim 18, the modified Miller discloses the method of claim 1 wherein the dielectric layer is metal-free ([0028] discloses: 215, grating layer, can be made of silicon, which is known in the art to be metal free).
Regarding claim 20, the modified Miller discloses the method of claim 1 wherein the dielectric layer consists of a single material ([0033] discloses: 215, grating layer, formed of silicon or tantala; thus considered to be one material).
Claims 5-6 are rejected under 35 U.S.C. § 103 as being unpatentable over Miller et al. (US 2018/0031744 A1, of record) in view of Greiner et al. (US 8,593,732 B1, of record), as applied to claim 1 above, in view of Greiner et al. (US 2015/0309220 A1, of record) hereinafter Greiner220.
Regarding claim 5, the modified Miller discloses the method of claim 4.
Miller fails to disclose a method wherein D is between 250 nm and 850 nm. Miller and Greiner220 are related because both disclose diffraction gratings.
Greiner220 teaches a method wherein D is between 250 nm and 850 nm ([0026] teaches: t=135 nm and h= 500 nm, giving D = 635 nm, which falls within the claimed range).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Miller in view of Greiner and provide a method wherein D is between 250 nm and 850 nm. Doing so would allow for increased diffraction efficiency over the desired wavelength range, thereby improving optical performance of the reflective grating.
Regarding claim 6, the modified Miller discloses the method of claim 5.
Miller fails to disclose a method wherein D is between 450 nm and 750 nm. Miller and Greiner220 are related because both disclose diffraction gratings.
Greiner220 teaches a method wherein D is between 450 nm and 750 nm ([0026] teaches: t=135 nm and h= 500 nm, giving D = 635 nm, which falls within the claimed range).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Miller in view of Greiner and provide a method wherein D is between 450 nm and 750 nm. Doing so would allow for increased diffraction efficiency over the desired wavelength range, thereby improving optical performance of the reflective grating.
Claim 17 is rejected under 35 U.S.C. § 103 as being unpatentable over Miller et al. (US 2018/0031744 A1, of record) in view of Greiner et al. (US 8,593,732 B1, of record), as applied to claim 1 above, in view of Hoose et al. (US 2002/0186926 A1).
Regarding claim 17, the modified Miller discloses the method of claim 1.
Miller fails to disclose a method wherein the immersion grating is characterized by a dispersion at Littrow of less than or equal to 2.0 radians/μm. Miller and Hoose are related because both disclose diffractive structures.
Hoose teaches a method wherein the immersion grating is characterized by a dispersion at Littrow of less than or equal to 2.0 radians/μm ([0060] teaches: 0.45 micron grating period, and operation around 1.4-1.6 microns, with angle of incidence of 28.96 degrees and diffraction angle of about 28 degrees, i.e., at Littrow, using applicants Littrow-dispersion definition; dispersion at Littrow is calculated to be 0.74 rad/ μm, which falls within the claimed range).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Miller in view of Hoose and provide a method wherein the immersion grating is characterized by a dispersion at Littrow of less than or equal to 2.0 radians/μm. Doing so would allow for controlled wavelength dependent diffraction, thereby improving spectral performance of the immersion grating.
Claim 19 is rejected under 35 U.S.C. § 103 as being unpatentable over Miller et al. (US 2018/0031744 A1, of record) in view of Greiner et al. (US 8,593,732 B1, of record), as applied to claim 1 above, in view of Lyu et al. (CN108761610, Examiner has provided a machine translation).
Regarding claim 19, the modified Miller discloses the method of claim 1.
Miller fails to disclose a method wherein the immersion grating is characterized by a diffraction efficiency greater than 99% over a wavelength range from 1041 nm to 1066 nm.
However, optimizing the diffraction efficiency over a specified wavelength range would have been within the level of ordinary skill and would only involve routine experimentation. See MPEP 2144.05 II (A). “Where the general conditions of a claim are disclosed in the prior art, it is not inventive to dis-cover the optimum or workable ranges by routine experimentation. ”In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, “a particular parameter must first be recognized as a result-effective variable, i.e., a variable which achieves a recognized result, before the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation ”In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). [I]f the prior art does recognize that the variable affects the relevant property or result, then the variable is result-effective. In the case at hand, Lyu in [0007] teaches center wavelength of 1064 nm and a 1st order diffraction efficiency of over 99%, and establishes the wavelength range as a variable which achieves a recognized result, i.e., a specified efficiency over the desired operating bandwidth, thereby reducing optical loss. Accordingly, it would have been obvious to one of ordinary skill in the art before the effective time of filing to disclose a method wherein the immersion grating is characterized by a diffraction efficiency greater than 99% over a wavelength range from 1041 nm to 1066 nm since it is not inventive to dis-cover the optimum or workable ranges by routine experimentation.
Compact Prosecution
Examiner recommends to overcome the current rejection, if supported by the specification, to amend the independent claims to include, wherein the dielectric layer has a total thickness between 450 nm and 750 nm, the periodic structure has a depth between 250 nm and 350 nm, and the immersion grating has a Littrow dispersion of ≤2.0 rad/micron and a diffraction efficiency of >99% over 1041 nm -1046 nm
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Hoose (US 2009/0059375 A1) and Li et al. (US 2009/0246707 A1) both disclose relevant optical systems but fails to disclose relevant grating alignment.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to John Sipes whose telephone number is (703)756-1372. The examiner can normally be reached Monday - Friday 4:30-9:30/12:30-7:30 (CT).
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Bumsuk Won can be reached at (571) 272-2713. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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John Sipes
Examiner
Art Unit 2872
/J.C.S./Examiner, Art Unit 2872
/BUMSUK WON/Supervisory Patent Examiner, Art Unit 2872
