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 .
DETAILED ACTION
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 and 2 are rejected under 35 U.S.C. 103 as being unpatentable over Yoshida et al. (2003/0063643) hereinafter ‘643 and further in view of Matsui (2021/0098967) hereinafter ‘967.
Fig 7 of ‘643 discloses a semiconductor laser device comprising:
1. “an active layer [3] to generate light;
a top cladding layer [4,6] disposed above the active layer [3], wherein the top cladding layer [4] is in direct contact with the active layer [3];
a bottom cladding layer [2] disposed below the active layer [3];
a front facet [15b] positioned at a first end [right side] of said active layer [3],
wherein the front facet is a light emitting facet coated with an AR-coating [15] (antireflection) with a reflectivity in the range of 0.01% to less than 0.5% in the spectral range of ±5nm from an operating center wavelength of semiconductor laser device [0.1% reflectivity at 1.48 µm];
a rear facet [14a] positioned on a second opposite end [left side] of said active layer [3] thereby forming a resonator between said front facet [15b] and said rear facet [14a]; and
a first order diffraction grating [13b] positioned within said resonator along only a portion [Lgb] of the length [L] of said active layer [3] and extending to and terminating at the rear facet [14a] (‘643 does not disclose the grating extending beyond the rear facet),
wherein the semiconductor laser device is arranged to emit light [200] from a single end [right side],
wherein the rear facet [14a] is a rear light reflecting facet with an HR-coating (highly reflective) [14] with reflectivity greater than or equal to 95% at the operating center wavelength [98% reflectivity at 1.48 µm],
wherein the diffraction grating [13b] extends from the rear light reflecting facet [14a] to a position between the front facet and the rear light reflecting facet [midway of the device],
wherein the diffraction grating [13b] has a grating length in the range of 0.5 mm to 3 mm [1600 µm], and
wherein the active layer [3] extends between and terminates at the front facet [15] and the rear facet [14].”
‘643 discloses a semiconductor laser device as described above, but does not disclose:
“wherein … the grating is … is positioned within the active layer”.
Instead, the reference discloses that the grating 13b is formed within a lower portion of the p-type cladding layer.
However, forming a grating either above or within the active layer, are well known alternatives in the art. Paragraph 0036 of ‘967 discloses forming the grating 306 in, on or above the active layer 308. Fig 3 of ‘967 also discloses that the grating 306 is extending to and terminating at the rear facet 305 and extends from the rear facet 305 to a position between the front facet 307 and the rear facet 305.
It would have been an obvious matter of design choice to one of ordinary skill in the art to incorporate the teaching of ‘967 into the device of ‘643 by positioning the grating within the active layer, to extend to and terminate at the rear facet, due to the equivalence of these positions of the grating in relation to the active layer within the resonator structure for its use in the semiconductor laser art and the selection of any of these known equivalents to provide feedback to the laser beam within the laser resonator would be within the level of one of ordinary skill in the art.
‘643 discloses HR rear reflector as described above, but does not specify verbatim:
“wherein the HR-coating of the rear light reflecting facet provides reflectivity lower than 93% at wavelengths other than the operating center wavelength.”
However, the reflectivity of the HR facet reflector is a result effective variable that determines the amount of light and the wavelength that is returned to the active layer and is predetermined by the materials used to make the reflector. The greater the reflectivity, the more light is returned to the active layer and contributes to the resonator and the less light escapes from the facet. Selecting high reflectivity at the center (desired) wavelength and low reflectivity at all other wavelength ensures that only the desired wavelength is resonated in the laser cavity. Therefore, it is either inherent that the HR coating of the device of ’643 has the specified reflectivity at undesirable wavelengths or it would have been obvious to make it so, for at least the purpose of obtaining an output that is centered only at the desired wavelength, as is customary for a laser.
Furthermore, HR reflectors with a reflectivity greater than 95% at the center wavelength and less than 93% at all other wavelengths are well known in the art, as evidenced by APA.
It would have been obvious to one of ordinary skill in the art before the filing date of the invention to modify the device of ‘643 by setting reflectivity of the HR coating 14 to have reflectivity less than 93% at wavelengths other than the operating center wavelength, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges or the optimum value for a result effective variable involves only routine skill in the art. In re Aller, 105 USPQ 233, In re Boesch, 617 F.2d 272,205 USPQ 215(CCPA 1980).
‘643 does not disclose verbatim that the grating 13b is “a first order grating”, however it is well known in the art, as evidenced by APA, that unless otherwise specified in a reference, the gratings are designed to be first order mode. Due to the nature and design of diffraction gratings, zero order represents no diffraction, first order represents highest intensity diffraction and lowest optical loss; the intensity decreases and optical loss increases with second and higher order modes. Therefore, it is either inherent that the grating 13b is a first order grating (since the order is not specified) or it would have been obvious to make it a first order grating for at least the purpose of producing high intensity diffraction and low optical loss.
‘643 further discloses:
2. “wherein the diffraction grating [13b] is a buried grating type.” The grating is not exposed.
Response to Arguments
Applicant’s arguments filed on 02/10/26 have been considered but they are not persuasive.
Regarding applicant’s arguments with respect to five differences between Yoshida ‘643 and the claimed invention:
“First … cladding layer 6 is separated from the active layer 3 by the spacer layer 4”. The examiner disagrees and points out that both layers 4 and 6 are composed of exactly the same material (p-type InP) and are shown to be in direct contact with each other. The definition of the term “cladding” is “a covering or coating on a structure or material”, it is clear that both layers 4 and 6 meet this definition. Therefore, the differences between these layers are semantic, they are different only in the name that the authors of the reference choose for them.
“Second … grating 13b is extending to a position near to the light reflecting coating and does not extend to and terminate at the rear facet”. The examiner disagrees and points out that it is well known in the art that the diffraction grating consists of several layers of alternating materials that have different indices of refraction, the interaction of incident light between these layers is how the grating provides reflection. The grating can also be formed by sawtooth shapes or indentations or openings provided in a layer of a single material, the openings can be filled with another material or with air. In ‘643 the first material is provided by the p-type InP layer itself, while the second material is illustrated by the five little rectangles formed of p-type InGaAsP. The main material has an index of refraction n1, while the rectangles have an index of refraction n2, therefore it is clear to anyone familiar with the art that the grating of the reference as starting from the facet is n1/n2/n1/n2/n1/n2/n1/n2/n1/n2. The fact that the last rectangle does not physically touch the facet 14 in Fig 7 does not mean that the grating does not extend to and terminated at this facet. It only means that the grating starts on n1 material as opposed to starting on n2 material. If it was not so and there was an intentional space left between the grating and the facet, then the device of ‘643 would have two cavities formed within it, one cavity between facet 15 and grating 13b and the second cavity between grating 13b and facet 14. However, no such second cavity is disclosed in the reference, it is clear that the grating 13b is formed at the end of the single cavity, because the device of ‘643 would not function as intended with two cavities instead of one.
Furthermore, the secondary reference ‘967 clearly shows that the grating 306 “extends to and terminates” at the rear facet 310. Therefore, the argument against ‘643 potentially not disclosing the claimed limitation is moot.
“Third … ‘643 does not disclose grating positioned at an interface between the active layer and the top cladding layer”. The examiner disagrees and points out that this limitation is claimed in the alternative with the limitation “grating is poisoned within the active layer”. Both alternative limitations cannot be true at the same time within a single device.
“Fourth … ‘643 does not disclose grating is poisoned within the active layer”. However, secondary reference ‘967 clearly describes in paragraph 0036 that the grating 306 can be formed in, on or above the active layer 308. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
“Fifth, … in ‘643 coating 14 does not provide reflectivity lower than 93% at wavelengths other than operating center wavelength.” However, this reflective range is disclosed by Admitted Prior art (APA), as is clearly stated in the rejection. The examiner took an official notice of this well-known on March 1, 2024, and it has not been challenged by the applicant.
For these reasons, the five differences presented by the applicant against ‘643 are not persuasive.
In response to applicant's argument that it is not obvious to combine ‘967 with ‘643, the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). In the present case, the teaching of ‘967 that the grating can be formed in, on or above the active layer are applicable to different configurations of edge emitting DFB lasers.
Regarding applicant’s arguments with respect to four differences between Matsui ‘967 and the claimed invention:
“First … grating 306 extends along the entire active region 304”, the examiner disagrees and points out that the limitation “active region” does not appear in the claims. Furthermore, the primary reference ‘643 already discloses the claimed limitation “grating [13b] positioned within said resonator along only a portion [Lgb] of the length [L] of said active layer”. ‘967 reference is a secondary reference used only for the purpose of showing that the grating 306 can be formed in, on or above the active layer 308. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
“Second … “HR coating does not provide reflectivity lower than 93% at wavelengths other than operating center wavelength.” The examiner disagrees and points out that this reflective range is disclosed by Admitted Prior art (APA), as is stated in the rejection. ‘967 reference is a secondary reference used only for the purpose of showing that the grating 306 can be formed in, on or above the active layer 308. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
“Third … in ‘967 the length of the grating is 50-200 µm, not 0.5 – 3 mm”. The examiner disagrees and points out that the 0.5 – 3 mm length range is supported by ‘643, as is stated in the rejection. ‘967 reference is a secondary reference used only for the purpose of showing that the grating 306 can be formed in, on or above the active layer 308. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
“Fourth … ‘967 does not disclose the active layer extends between and terminates at the front facet and the rear facet”. The examiner disagrees and points out that the active layer 3 extending between facets 14 and 15 is supported by ‘643, as is stated in the rejection. ‘967 reference is a secondary reference used only for the purpose of showing that the grating 306 can be formed in, on or above the active layer 308. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
For these reasons, the four differences presented by the applicant against ‘967 are not persuasive.
In response to applicant's argument that ‘967 and ‘643 are nonanalogous art, it has been held that a prior art reference must either be in the field of the inventor’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned, in order to be relied upon as a basis for rejection of the claimed invention. See In re Oetiker, 977 F.2d 1443, 24 USPQ2d 1443 (Fed. Cir. 1992). In this case, both references are directed to edge emitting DFB semiconductor lasers. The fact that one of the references has an additional passive etalon section for modifying cavity loss dynamics due to frequency chirp when the active section is modulated, does not change the applicability of the teaching for where in the active layer of the active section of the laser the grating can be placed so as to provided desired feedback properties to the oscillating wavelength.
For these reasons, one of ordinary skill in the art would have been motivated to combine the two references as they are both in the field of the inventor’s endeavor.
Admitted Prior Art
The rejection of claim 1 (reflectivity of HR coating and 1st order diffraction grating) based on the well-known in the art statement is taken to be admitted prior art (hereinafter APA) because applicant either failed to traverse the examiner’s assertion of official notice or that the traverse was inadequate, see MPEP 2144.03.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Contact Info
Any inquiry concerning this communication or earlier communications from the examiner should be directed to M. A. GOLUB-MILLER whose telephone number is (571)272-8602. The examiner can normally be reached on M-F 9-5.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, MinSun Harvey can be reached on (571) 272-1835. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/M. A. Golub-Miller/Primary Examiner, Art Unit 2828