Non-Final Rejection
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Following a preliminary amendment, claims 1-18 are pending.
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 1-12 and 15-17 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al., "Ridge-Width Dependence of the Dispersion and Performance of Mid-Infrared Quantum Cascade Laser Frequency Combs", 2020 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), May 2020, pages 1-2 (“Wang”) in view of US 2015/0103857 to Maulini et al. (“Maulini”).
It is noted that Wang was published less than 1 year prior to the effective filing date, and the current inventors Wang and Faist are also authors of the Wang reference. However, the reference also includes three additional authors who are not inventors here, therefore the reference is prior art at this time. MPEP 2153.01(a) (“If, however, the application names fewer joint inventors than a publication (e.g., the application names as joint inventors A and B, and the publication names as authors A, B and C), it would not be readily apparent from the publication that it is an inventor-originated disclosure and the publication would be treated as prior art under AIA 35 U.S.C. 102(a)(1) unless there is evidence of record that an exception under AIA 35 U.S.C. 102(b)(1) applies.”). Applicant may file a declaration under 37 CFR 1.130(a), if appropriate, to remove this reference as prior art. See MPEP 717 for requirements. This would also apply to the other rejections below.
Regarding claim 1:
1. A cascade laser having an operating wavelength range over which it is operable to output a frequency comb, the laser comprising end mirrors that form a resonant cavity and a waveguide arranged between the end mirrors, the waveguide comprising: a narrow part that supports at least a fundamental mode across the operating wavelength range and enhances optical non-linearity to improve generation of a frequency comb via four-wave mixing;
Wang describes a cascade laser having an operating wavelength range over which it is operable to output a frequency comb (see e.g. Fig. 2(e); first sentence of introduction), the laser comprising end mirrors (see first page, second paragraph: Fabry-Perot laser cavity is formed between two cleaved facets) that form a resonant cavity and a waveguide (buried heterostructure with wet etched laser ridges and lateral InP:Fe insulating layer) arranged between the end mirrors, the waveguide comprising: a narrow part (5.5 µm wide ridge) that supports at least a fundamental mode across the operating wavelength range and enhances optical non-linearity to improve generation of a frequency comb (see second sentence of introduction; see also page 2, first paragraph: a stable frequency comb is obtained when the GVD is negative, as is the case for a 5.5 um wide ridge, see Fig. 2(b)) via four-wave mixing (see first page, first paragraph).
and a wide part having a width greater than the narrow part, wherein the narrow and wide parts are configured in combination such that the laser is operable to produce lasing only in the fundamental mode across the operating wavelength range for frequency comb generation.
Wang does not have a wide part greater than a narrow part configured in combination such that the laser is operable to produce lasing only in the fundamental mode across the operating wavelength range for frequency comb generation.
Maulini teaches that a quantum cascade laser may be tapered to have wider ends at the facets. It would have been obvious to a person of ordinary skill in the art to do this as it maintains the power but reduces heating and thus damage at the facets, as taught by Maulini. [0006]. Maulini also teaches at [0006] that the narrow section width is designed to select the desired 0th order mode, i.e. supports the fundamental mode.
Regarding claims 2 and 3, Wang Figs. 2(a)-(b) show examples of GVD that are below 700 fs2/mm and that have very little variation over the operating wavelength range.
It is noted that several claims contain plural different requirements. For example, claim 2 requires the GVD to be below one of 700, 600, 500, 400, 300, 200, and 100. It is not clear why applicant wrote the claims this way, but the broadest reasonable interpretation of the claim is just that the broadest limitation must be met; in the case of claim 2 the GVD must just be below 700. That is, the claims are not indefinite, just broader than they may seem to be written.
Regarding claims 4-6, applicant is just claiming the general properties of the device without claiming any structure that is supposed to achieve those properties. The combined device of Wang and Maulini meets the same general structure as in the rejection of claim 1 above. When the claim and prior art have substantially the same structure, claimed properties are presumed to be inherent. If applicant can claim a structure that causes such properties and also that is different than the prior art that would be more persuasive. It is also noted that Wang does show example ridges in Figs. 2(a)-(b), which are the narrow parts, with negative GVD and/or negative GVD slope.
Regarding claim 7, Maulini states that the taper length may be 50% of the total length of the laser, Table 2 at [0024], so it is greater than 50% of the length of the narrow part.
Regarding claim 8, Maulini states that the taper length may be 50% of the total length of the laser, Table 2 at [0024], which touches the claimed range. When the claim range and prior art range touch there is overlap, and thus a prima facie case of obviousness. See MPEP 2144.05 I.
Regarding claim 9, Wang discloses in section 2, first paragraph, that the laser is formed in a ridge waveguide. There is a top cladding which implies there must also be a bottom cladding to provide the waveguiding and vertical confinement. Wang uses lateral InP:Fe insulating layers that will provide lateral confinement of the waveguiding modes. This is a quantum cascade laser and these always have quantum wells.
Regarding claim 10, Wang says this is a quantum cascade laser.
Regarding claim 11, Wang is a quantum cascade laser, not an interband cascade laser. These laser types are not the same but share many similarities with the primary difference being the specific quantum wells, and the general principles of Wang are likewise applicable to ICLs. That is, it would have been obvious to a person of ordinary skill in the art to reconfigure the combined device as an ICL. It should be noted that applicant’s entire detailed description is drawn to QCLs not ICLs, so applicant essentially assumes that reconfiguring one to the other would have been easy to a person of ordinary skill in the art, otherwise claim 11 would likely not be enabled.
Regarding claim 12, in Wang facets provide the end mirrors. Page 1 last sentence above figures.
Regarding claims 15-17, it is somewhat arbitrary where the “narrow” part ends and the “wide” part begins, and one can simply say the first part of the tapered part closest to the center of Maulini is still part of the “narrow” part and the outer part is the “wide” part. In this case each of the narrow and wide parts have tapered sections as claimed.
Claims 1-12 and 15-17 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of DE 10 2017 114 732 (“DE ‘732”) (translation in file).
Regarding claim 1:
1. A cascade laser having an operating wavelength range over which it is operable to output a frequency comb, the laser comprising end mirrors that form a resonant cavity and a waveguide arranged between the end mirrors, the waveguide comprising: a narrow part that supports at least a fundamental mode across the operating wavelength range and enhances optical non-linearity to improve generation of a frequency comb via four-wave mixing;
and a wide part having a width greater than the narrow part, wherein the narrow and wide parts are configured in combination such that the laser is operable to produce lasing only in the fundamental mode across the operating wavelength range for frequency comb generation.
Wang shows these limitations as in the first rejection above, but does not have a wide part greater than a narrow part configured in combination such that the laser is operable to produce lasing only in the fundamental mode across the operating wavelength range for frequency comb generation.
DE ‘732 describes a quantum cascade laser tapered to have wider ends at the facets. Fig. 1. It would have been obvious to a person of ordinary skill in the art to do this as it increases the power but still limits higher modes, as taught by DE ‘732. [0009]-[0011].
Regarding claims 2-6 and 9-12, see the above rejection of these claims.
Regarding claim 7, for DE ‘732, it is arbitrary which part we call the wide part and the narrow part, therefore we can consider the wide part as much greater than the narrow part and thus the reference meets the claim
Regarding claim 8, for DE ‘732, it is arbitrary which part we call the wide part and the narrow part, therefore we can consider the wide part as much greater than the narrow part and thus the reference meets the claim.
Regarding claims 15-17, it is somewhat arbitrary where the “narrow” part ends and the “wide” part begins, and one can simply say the first part of the tapered part closest to the center of DE ‘732 is still part of the “narrow” part and the outer part is the “wide” part. In this case each of the narrow and wide parts have tapered sections as claimed.
Claims 13, 14, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Wang and Maulini as applied to claim 1, and further in view of US 2024/0097404 to Mawst et al. (“Mawst”).
Claims 13, 14, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Wang and DE ‘732 as applied to claim 1, and further in view of Mawst.
Regarding claims 13, 14, and 18, Maulini and DE ‘732 do not exactly show the shapes of the waveguide sections as claimed. Each claim would be met if the wide part had a section of constant width at the end of the waveguide (rather than being tapered the entire way) and for DE ‘732 if part of the narrow part was also constant width. Mawst shows a quantum cascade laser with narrower parts and wider parts and also tapered parts. Mawst shows in Fig. 1 that the entire part may be tapered, but also shows in Fig. 3 that there may be constant width parts at the narrow and wide ends with tapered part in between. Mawst further suggests that the actual number of tapered or straight (called collateral) sections and their relative arrangement does not matter, so long as they can achieve single mode and high output power operation. [0059]. These goals are similar to those of Maulini and DE ‘732. It therefore would have been obvious to a person of ordinary skill to include various constant width sections at the end of the waveguides, as Mawst suggests this is a mere change in shape style of design choice.
Conclusion
Other quantum cascade lasers with tapered cavities are cited.
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/JAMES A MENEFEE/ Primary Examiner, Art Unit 2828