DETAILED ACTION
This office action is response to applicant’s amendment filed on 11/5/2025. Claims 1-6 are under consideration.
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 1-7 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.
As stated in the previous office action, claim 1 defines a mode conversion device comprising a long period grating. To make the claimed long period grating, one would need to be able to calculate the grating pitch Λ and the grating coupling length Lc. Although value ranges have ben provided for FWHM, coupling efficiency C, and core diameter, the equations in claim 1 and 7 remain indefinite because there are more unknown variables than equations.
The propagation constant β can be solved with
β
=
n
e
f
f
2
π
λ
; the effective refractive index neff requires at least ncore or ncladding known. Thus, the propagation constant is indefinite.
There is no defined value or range for β , Lc, and Lg, which renders the metes and bounds of the claim indefinite.
For the reasons above, the claims remain indefinite.
Claim Rejections - 35 USC § 102
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.
Claims 1 and 6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Urushibara et al. (US 2019/0187365 A1, herein “Urushibara”).
Regarding claims 1 and 6, Urushibara discloses a mode conversion device (91 in Fig. 1) comprising a long period grating (LPG for the mode converter, Para [0052]) at a core of the optical fiber (Fifth Embodiment teaches the mode converter 91 is a grating that is formed using a CO2 laser or a UV laser to change the refractive index, Para [0068]) from one mode to another mode (LP01 and LP11a LP11b, Para [0045]-[0048]). Urushibara implicitly teaches altering the refractive index of the core of the fiber in the disclosure of the bending species of the mode converter (Para [0069]). Furthermore, the mode conversion of interest is guided within the core. By matching the grating pitch of the LPG with
2
π
Δ
β
mode coupling between modes can occur (Para [0055]). Fig. 6 further shows the center wavelengths of three different fiber core diameters (8.4 microns, 12 microns, and 13.4 microns) are greater than 1250 nm and their respective refractive index difference is greater than 0.28% (1.0%, 0.5%, and 0.4%). Therefore, the examiner considers the mode converter 91 as disclosed by Urushibara inherently has values that meet the equations set forth.
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 2-5 are rejected under 35 U.S.C. 103 as being unpatentable over Urushibara in view of Grubsky et al. (US 2002/0122629 A1, herein “Grubsky”).
Urushibara discloses the invention of claim 1, however, Urushibara does not teach a tap waveguide that is at a rear stage of the long period grating in a propagation direction of light and outputs from a side surface of the optical fiber, light with a desired wavelength converted from one mode to another mode by the long period grating in light propagating through the core of the optical fiber.
Grubsky teaches mode conversion device comprising a tap waveguide (18 in Fig. 1A) that is at a rear stage of the long period grating (22) in a propagation direction of light and outputs, from a side surface of the optical fiber, light with a desired wavelength converted from one mode to another mode by the long period grating in light propagating through the core of the optical fiber (Para [0027], [0047]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the transmission line with mode converter of Urushibara with a tap waveguide to transfer light at a desired and selected wavelength from the core of one optical fiber into the core of another optical fiber through a coupling region. One motivation would be to efficiently transmit the selected wavelength out of a transmission fiber that carry many optical channels which have application in communication systems that use wavelength division multiplexing (Para [0003] and [0009]).
Claim 3. Urushibara in view of Grubsky (herein “Urushibara / Grubsky”) teach a set of long period grating and the tap waveguide is vertically aligned in the optical fiber (Grubsky: Fig. 1a).
Claim 4. Urushibara / Grubsky teach the long period grating has different design parameters so that wavelengths of light converted from the one mode to the other mode are different from each other. Grubsky teaches the general condition of phase matching condition between the two coupled optical modes. This happens when the period of the grating GAMMA, satisfies the phase-matching condition. For given values of effective refractive index of the core, effective refractive index of the clad, and wavelength, the phase matching condition predicts a certain value for the resonant wavelength lambda. Therefore, long-period gratings are wavelength-selective elements. In other words, converted wavelengths of light from the one mode to the other mode are different from each other (Grubsky: Para [0042-0043]).
Claim 5. Urushibara / Grubsky teach the general condition for varying the long period grating length GAMA. Moreover, Grubsky discloses coupling efficiency between different mode converters through experimentation, and found coupling efficiency may varies (e.g., 99% in Para [0047]), and 16% in Para [0050]). Thus, Grubsky teaches the grating length Lg of the long period grating is different so that a wavelength of light to be converted from one mode to another mode is identical and the coupling efficiency is different.
Response to Arguments
Applicant’s arguments with respect to claims 1-6 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. New ground of rejection to over Urushibara teach the fiber having the characteristics as recited in claim 1 and claim 6, thus Urushibara inherently has values that meet the equations set forth in the claims.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Erin D Chiem whose telephone number is (571)272-3102. The examiner can normally be reached 10 am - 6 pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Thomas A. Hollweg can be reached at (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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/ERIN D CHIEM/Examiner, Art Unit 2874
/THOMAS A HOLLWEG/Supervisory Patent Examiner, Art Unit 2874
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