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 .
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.
Election/Restrictions
Applicant’s election without traverse of invention II in the reply filed on 12/5/2025 is acknowledged.
Claim Rejections - 35 USC § 103
Claims 9-18 are rejected under 35 U.S.C. 103 as being unpatentable over US 2015/0071322 (Haensel) in view of US 2002/0181824 (Huang) and US 2023/0006407 (Underwood).
For claim 9, Haensel teaches an electrically tunable non-reciprocal phase shifter (fig. 6, [0086]-[0087]), comprising:
a polarizing beam splitter device (fig. 6, 26; [0087]);
a Faraday rotator (fig. 6, 32, [0087]);
a modulation device (fig. 6, 34; [0087]; [0084] teaches using an EOM device as an adjustable phase shifting element); and
a fiber coupler (fig. 6, 30, [0086]);
wherein the phase shifter is configured:
to couple two beams of light to two axis the modulation device, respectively (axis corresponding to the polarizations of the PBS); and
to be element adjustable with respect to its phase shifting properties, so as to control a non-reciprocal linear phase shift amount of the light ([0084]; “phase shift element 34 will be adjustable with respect to its phase shifting properties…it may be an electro optic modulator”).
Haensel does not teach details of the polarizing beam splitter; specifically, Haensel does not teach the polarizing beam splitter is a birefringent crystal device. However, Huang teaches a birefringent crystal wedges may be used to form a polarizing beam splitter ([0032]). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use birefringent crystal wedges as taught by Huang in order to form the polarizing beam splitter device of Haensel.
The combination of Haensel and Huang does not teach the modulation device/phase shift element 34 is a modulation crystal device with fast and slow axis where the refractive index difference between the fast and slow axis is changed to introduce different phase delays for the two beams of the light so as to control a phase shift amount between the two beams of the light.
However, Underwood teaches an electro optic phase modulator (fig. 2, 22) which is a modulation crystal device with fast and slow axis where the refractive index difference between the fast and slow axis is changed to introduce different phase delays for the two beams of the light so as to control a phase shift amount between the two beams of the light ([0028]) in order to maximize difference in optical path lengths ([0029]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the modulation crystal device of Underwood in the previous combination in order to maximize difference in optical path lengths.
For claim 10, Underwood teaches the modulation crystal device comprises a potassium dihydrogen phosphate (KDP) crystal, a lithium niobate (LiNbO3) crystal, a gallium arsenide (GaAs) crystal, a lithium tantalate (LiTaO3) crystal, or a combination thereof ([0028]).
For claim 11, Underwood teaches the modulation crystal device is a LiNbO3 crystal device ([0028]). The limitation “a refractive index ellipsoid of the modulation crystal device is rotated through 45º along a z-axis in a principal axis coordinate system by applying a voltage on an x-axis of the modulation crystal device” recites a use of the device, and a claim containing a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus if the prior art apparatus teaches all the structural limitations of the claim. See MPEP 2114. As described in the rejection of claim 9 and 11 above, the structural limitations are met.
For claim 12, Underwood teaches a voltage is applied to enable arbitrary phase delay ([0029]).
The combination inherently teaches “when a DC voltage is applied, a fixed non-reciprocal linear phase difference is provided to form a fixed phase shifter; and when an AC voltage is applied, an adjustable non-reciprocal linear phase difference is provided to form an adjustable phase shifter.” The structure is substantially similar to the claimed invention and will, therefore, have the same response when a DC and AC voltage is applied.
For claim 13, Haensel teaches the birefringent crystal device is selected from a polarizing beam splitter (PBS), a calcite crystal device, a Wollaston prism, or a combination thereof (fig. 6, 26; [0087]).
For claim 14, the combination does not teach the Faraday rotator is configured to rotate a polarization state of light through 45º to make the light incident along the fast or slow axis of the modulation crystal device. However, rotation is a results effective variable. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to optimize the rotation of the Faraday rotator in order to optimize interference of counter propagating beams, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
For claim 15, the combination is applied according to the rejection of claim 9 above. Haensel further teaches the electrically tunable non-reciprocal phase shifter according to claim 9 is used in a nonlinear amplifying loop mirror (NALM) mode-locked laser ([0019], [0067]). Haensel further teaches the phase shifter configured to provide adjustable non-reciprocal linear phase shift for two beams of light that transmit in forward and reverse directions in a nonlinear loop, so as to implement mode-locking of the laser ([0030]).The combination does not explicitly state the phase shifter is configured as a phase-locked element for locking a repetition frequency signal fr or a carrier-envelope offset signal fo. However, the limitation appears to be a recitation of the intended use of the device rather than provide an actual structural distinction, and a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus if the prior art apparatus teaches all the structural limitations of the claim. See MPEP 2114. As described in the rejection of claim 9 and 11 above, the structural limitations are met.
For claim 16, the combination is applied according to the rejection of claim 9 above. Haensel further teaches a Sagnac loop (fig. 6, PBS 26 is the entry/exit point ([0087])) comprising the electrically tunable non-reciprocal phase shifter according to claim 9, wherein the electrically tunable non-reciprocal phase shifter is used in the Sagnac loop to provide electrically-controlled adjustable non-reciprocal linear phase shift for two beams of light that transmit in forward and reverse directions ([0087], counter propagating pulses) to change output characteristics of the Sagnac loop ([0084], adjustable EOM; [0087]).
For claim 17, Haensel teaches a Sagnac laser (fig. 6) is actively mode-locked by changing a voltage applied on the electrically tunable non-reciprocal phase shifter ([0030] and [0084] via the adjustable EOM/the modulation device). Further, the limitation “is actively mode-locked by changing a voltage applied on the electrically tunable non-reciprocal phase shifter” appears to be a recitation of the intended use of the device rather than provide an actual structural distinction, and a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus if the prior art apparatus teaches all the structural limitations of the claim. See MPEP 2114.
For claim 18, Haensel teaches the electrically tunable non-reciprocal phase shifter is configured as a phase-locked element of a Sagnac laser (fig. 6 and ([0019], [0067]).
The combination inherently teaches “when a DC voltage is applied on the electrically tunable non-reciprocal phase shifter, a fixed non-reciprocal linear phase shift amount is provided; when an AC voltage is applied on the electrically tunable non-reciprocal phase shifter, an adjustable non-reciprocal linear phase shift amount is provided.” The structure is substantially similar to the claimed invention and will, therefore, have the same response when a DC and AC voltage is applied.
Haensel does not explicitly teach and the phase-locked element of the Sagnac laser is configured to lock a repetition frequency signal fr. However, the limitation appears to be a recitation of the intended use of the device rather than provide an actual structural distinction, and a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus if the prior art apparatus teaches all the structural limitations of the claim. See MPEP 2114. As described in the rejection of above, the structural limitations are met.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Michael W Carter whose telephone number is (571)270-1872. The examiner can normally be reached M-F, 9:00-5:30.
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/Michael Carter/ Primary Examiner, Art Unit 2828