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 .
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 1-4 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.
Claim 1 recites: “an N-input-1-output first optical switch that switches an optical signal received by the optical reception unit; a 1-input-N-output second optical switch provided upstream of the optical signal with respect to the first optical switch; and N optical waveguides of different lengths connected between the first optical switch and the second optical switch, and the optical signal input to the second optical switch is input to the first optical switch through one of the optical waveguides and received by the optical reception unit.”
The claim is indefinite for at least the following reasons:
Inconsistent switch architecture / unclear signal path
The claim recites a first optical switch as an N-input-1-output switch, while also stating that the optical signal is input to the second optical switch, passes through one of the optical waveguides, is input to the first optical switch, and is then “received by the optical reception unit.”
However, the claim further states that the first optical switch is one that “switches an optical signal received by the optical reception unit,” which does not clearly identify the direction of signal flow or the function of the first optical switch.
As a result, it is unclear whether the first optical switch is upstream or downstream of the second optical switch, and the claimed signal path cannot be determined with reasonable certainty.
Ambiguous “upstream of the optical signal with respect to the first optical switch” language
The phrase “provided upstream of the optical signal with respect to the first optical switch” is grammatically and technically unclear.
It is not reasonably clear what component is “upstream,” relative to what signal path, or how the recited optical signal is being routed through the switches and waveguides.
Lack of antecedent clarity as to the recited optical signal
The claim refers to “the optical signal” in multiple places without clearly and consistently defining the same signal flow.
It is unclear whether the optical signal is received from the network, output from the second optical switch, or processed by the first optical switch before reception.
Because the scope of claim 1 cannot be determined with reasonable certainty, claim 1 is indefinite under 35 U.S.C. 112(b).
Claim 2 depends from claim 1 and therefore inherits the indefiniteness of claim 1. Additionally, the phrase: “operate with a transient response time same as or shorter than a transient response time of an optical switch used to change a propagation path of the optical signal in the network” is unclear because:
“same as or shorter than” is imprecise wording and should be recited more clearly, e.g., “equal to or shorter than.”
“an optical switch used to change a propagation path of the optical signal in the network” does not clearly identify the reference optical switch.
Thus, claim 2 is also indefinite.
Claim 3 depends from claim 1 and therefore inherits the indefiniteness of claim 1. In addition, claim 3 recites: “a time required for the optical signal input to the second optical switch to propagate by \u0394L through the optical waveguide is equal to a time ((1/(symbol rate))/N) obtained by dividing the reciprocal number of the symbol rate by the N.”
This limitation is unclear because:
the expression is awkwardly phrased and does not clearly define the relationship between propagation delay, symbol rate, and N;
it is unclear whether the limitation requires exact equality, approximation, or a design target;
the term “the reciprocal number of the symbol rate” is not a standard claim expression and creates ambiguity as to the intended meaning.
Accordingly, claim 3 is indefinite.
Claim 4 depends from claim 1 and therefore inherits the indefiniteness of claim 1. The claim also recites: “the first optical switch and the second optical switch are waveguide-type optical switches formed on a silicon substrate and manufactured by a planar lightwave circuit technology made of silica-based glass containing SiO2 as a main component, and are driven by using a thermo-optical effect.”
The limitation is unclear because:
it is not clear whether the recited structural features are intended as affirmative limitations of the claimed optical transceiver or merely as exemplary implementation details;
the phrase “manufactured by a planar lightwave circuit technology made of silica-based glass containing SiO2 as a main component” is awkward and lacks precision as to what structure is required.
Thus, claim 4 is indefinite.
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.
Claim(s) 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Lim et al. (US 2020/0028590 A1) in view of Mehrvar et al. (US 2021/0014584 A1).
Regarding claim 1, Lim et al. disclose an optical repeater system including a master unit, a plurality of remote units, and an optical delay control device configured to compensate for propagation delay times of multiple paths by selectively connecting cable members having different lengths through optical switches. See, for example, paragraphs [0021], [0084]-[0104], and [0093]-[0100]. In particular, teaches that optical switches are used to selectively connect plural delay elements of different lengths on each delivery path so that a propagation delay time can be compensated by selecting an appropriate cable length combination.
Mehrvar et al. disclose a tunable optical delay line including a coarse delay portion and a fine delay element, wherein the coarse delay portion includes a coarse delay selection element in conjunction with a coarse delay element, the coarse delay selection element being incorporated on-chip into a photonic integrated circuit component, the coarse delay element being disposed off-chip of the photonic integrated circuit component and interconnected with the coarse delay selection element. See, for example, paragraphs [0008]-[0016], [0033]-[0039], and [0044]-[0048]. Mehrvar et al. further teach that the coarse delay element may comprise a set of 1×N and N×1 optical switching elements selectable to provide a coarse delay amount, with delay elements of different lengths connected therebetween.
It would have been obvious to one of ordinary skill in the art at the time of the invention to modify the delay compensation arrangement of Lim et al. using the selectable optical switching and delay-line architecture of Mehrvar et al. in order to provide a compact optical transceiver arrangement having selectable optical waveguides of different lengths for controlling signal timing at the receiver. Both references address the same problem of compensating for optical signal delay by selecting among different optical path lengths, and the proposed combination merely uses known optical switching and delay-line techniques for their expected and predictable results.
More specifically, Lim et al. teach selectively connecting delay paths of different lengths to compensate for propagation delay, and Mehrvar et al. teach implementing such selectable delay paths with optical switching elements and optical delay elements in a photonic integrated circuit environment. Therefore, providing an N-input-1-output first optical switch, a 1-input-N-output second optical switch, and N optical waveguides of different lengths between the switches, as recited in claim 1, would have been an obvious design choice to one skilled in the art seeking to implement selectable propagation-delay compensation in an optical transceiver.
Claim 2 depends from claim 1 and further recites that the first optical switch and the second optical switch operate with a transient response time same as or shorter than a transient response time of an optical switch used to change a propagation path of the optical signal in the network.
Lim et al. teach optical switches used to change propagation paths in an optical repeater network. Mehrvar et al. teach selectable optical switching elements used in a tunable delay line. It would have been obvious to select optical switches having a transient response time equal to or shorter than that of the network path-changing switch, because the switching speed of optical routing elements is a known design parameter and matching or improving response time relative to the network switch would have been a routine optimization to ensure proper timing and avoid added delay. Accordingly, claim 2 would have been obvious over the combined teachings of the cited references.
Claim 3 depends from claim 1 and recites that, among the N optical waveguides of different lengths, a shortest optical waveguide having a shortest length and other optical waveguides have different lengths by n×ΔL, and that a time required for the optical signal input to the second optical switch to propagate by ΔL through the optical waveguide is equal to a time (1symbol rate)/N obtained by dividing the reciprocal number of the symbol rate by N.
Mehrvar et al. teach tuning optical delay by combining coarse and fine delay amounts and selecting optical delay values in a controlled manner. Lim et al. teach selectively compensating propagation delay by choosing among cable members of different lengths. It would have been obvious to one of ordinary skill in the art to set the different waveguide lengths in increments corresponding to a predetermined delay interval based on system timing, including a fraction of a symbol period, in order to allow the receiver timing to remain synchronized without adjusting the read timing after each path change. Such delay spacing is merely an optimization of known selectable-delay structures to meet known timing requirements in an optical network. Therefore, claim 3 would have been obvious over the combined teachings of the references.
Claim 4 depends from claim 1 and recites that the first optical switch and the second optical switch are waveguide-type optical switches formed on a silicon substrate and manufactured by planar lightwave circuit technology made of silica-based glass containing SiO2 as a main component, and are driven by using a thermo-optical effect.
Mehrvar et al. teach optical delay lines and optical switching elements implemented in photonic integrated circuit technology, including silicon photonic switching elements. Lim et al. teaches optical switching and delay compensation in an optical communication network. It would have been obvious to one of ordinary skill in the art to implement the selectable optical switches of the combined system as waveguide-type optical switches on a silicon substrate and/or in planar lightwave circuit technology using silica-based glass and thermo-optic operation, because such implementations were well-known and routinely used for integrated optical switching with low loss, high reliability, and compact form factor. Accordingly, claim 4 would have been obvious over the cited references.
Conclusion
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/QUAN ZHEN WANG/Supervisory Patent Examiner, Art Unit 2685
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