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 . This application was filed with claims 1-34. By preliminary amendment filed 7/13/2023, claims 1-2, 6, 8, 14-15, 18-19, 23, and 31-32 are amended, and claims 3, 7, 11-13, 17, 20-21, 24, 27-30, and 34 are cancelled. Claims 1-2, 4-6, 8-10, 14-16, 18-19, 22-23, 25-26, and 31-33 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 1-2, 4-5, 8-10, 14, 18-19, 22, 25-26, and 31 are rejected under 35 U.S.C. 103 as being unpatentable over US 2009/0296753 to Kato (“Kato”) in view of US 4,932,034 to Usami et al. (“Usami”), and further in view of Bobbs et al, Tunable DFB semiconductor lasers with active feedback for frequency stability (“Bobbs”) (see 1/23/2023 IDS for full citation).
Regarding claim 1:
1. A laser having a narrow linewidth, the laser comprising:
a grating along a laser cavity;
a laser waveguide having a plurality of waveguide sections corresponding to a plurality of grating sections, each of the plurality of waveguide sections having a ridge/mesa width
Kato discloses in the second embodiment, Figs. 7-9, starting at [0080], a laser having a grating 28 along a laser cavity and a waveguide having a plurality of waveguide sections at 26A, 36B, 36C corresponding to a plurality of grating sections. Each of the waveguide sections has a ridge/mesa width as is clear in Figs. 7 (dashed lines) and 9A-B showing cross sections with different widths. The preamble statement that the laser has a narrow linewidth is considered a desired result or purpose and does not make any structural requirement, therefore it is not considered limiting. MPEP 2111.02. But in any case, frequency tuning like in Kato or frequency stabilization like in Bobbs would help to narrow the linewidth.
for detuning the grating in each of the plurality of grating sections; and
Kato does not disclose that the ridge/mesa width is “for detuning the grating.” As noted Kato has section having different ridge widths and different electrodes over those sections. This is apparently exactly how the detuning is achieved in the present invention, therefore these areas in Kato can likewise be said to be “for” this. When the structure in the reference is substantially identical to that of the claim, claimed properties or functions like this are presumed inherent. See MPEP 2112.01 I.
a plurality of contact electrodes contacting each of the plurality of waveguide sections, the plurality of contact electrodes for applying a different current to each of the plurality of waveguide sections to enable active feedback noise suppression.
Kato shows a plurality of contact electrodes 30A-C contacting each of the plurality of waveguide sections for applying a different current to the sections.
One might argue that sections 30A and C get the same current and therefore “each” does not get a different current. Usami teaches that in a DFB laser it may be advantageous to have a plurality of electrodes for driving the laser where each electrode gets a different current. See Fig. 2A or 4A showing lasers with multiple electrodes driven by multiple current sources, and Figs. 2B and 4B showing the injected current in each electrode differs. It would have been obvious to a person of ordinary skill in the art to do so as it allows one to make the carrier density. It would have been obvious to a person of ordinary skill in the art to have separate injection currents as this helps to provide a stable and high power output. Col. 6 line 40 to col. 7 line 5.
The current to the electrodes is also not described “to enable active feedback noise suppression.” Bobbs teaches that a DFB laser may be part of an active feedback system to help suppress noise. Fig. 1. It would have been obvious to a person of ordinary skill in the art to include this as noise suppression is clearly desirable in many applications.
Regarding claim 2, the grating of Kato is periodic, i.e. a uniform period. [0083].
Regarding claim 4, as seen in Kato Fig. 7 the lengths of the plurality of contact electrodes 30A-C for applying a different current to the plurality of waveguide sections are different from lengths of the plurality of waveguide sections (dashed lines, see Fig. 7).
Regarding claim 5, Kato’s laser is a buried heterostructure type device. See Figs. 9A-B.
Regarding claims 8-10, Kato’s waveguide sections have a central section having a first ridge width, and first and second end sections having a second ridge width, the first and second widths are different. See Fig. 7, 9A, 9B.
Regarding claim 14, Kato discloses that one of the ends of the laser may be highly reflective by placing a HR film on one end. [0051]. Kato therefore discloses the claim except does not disclose that it is a cleaved facet. The examiner takes Official Notice that semiconductor lasers are very typically cleaved in forming them, and the cleavage plane often times is of sufficiently high reflectivity to be used as a highly reflective laser reflector. It would have been obvious to a person of ordinary skill in the art to use cleavage instead of an HR film as this is merely a simple substitution of one known element for another to yield predictable results. See MPEP 2143 I.B. The necessary findings are clear above. Additionally, the result of the substitution would have been predictable because both techniques yield a similar result, a laser having a reflective end.
Claims 18-19, 22, 25-26, and 31 are substantially the same as claims 1-2, 5, 8-9, and 14-16 respectively, except they are drawn to the method of fabricating the laser. The method steps are just “providing” the various parts and thus are necessarily met by the laser and the claims are met for the same reasons as the corresponding device claim above.
Claims 6 and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Kato, Usami, and Bobbs as applied to claim 1, and further in view of US 2010/0150579 to Mori (“Mori”).
Regarding claims 6 and 23, the parent claims are taught as above. Kato does not show that at least on of the end waveguides is curved or tapered. Mori shows a similar device and shows in Fig. 13, [0225]-[0230] that an end waveguide (part under electrode 411) may be curved and tapered. It would have been obvious to a person of ordinary skill in the art to do this as Mori teaches that this provides an effective chirped grating even with a periodic grating and have a large sweep width. It also allows the waveguide to be oblique to the end face, changing the reflectance and improving the spectrum, as taught by Mori. [0230].
Claims 15-16 and 32-33 are rejected under 35 U.S.C. 103 as being unpatentable over Kato, Usami, and Bobbs as applied to claim 1, and further in view U.S. 6,064,681 to Ackerman (“Ackerman”).
Regarding claim 15, as discussed above it would have been obvious to a person of ordinary skill in the art to use the feedback system of Bobbs for active noise suppression. Bobbs Fig. 1 shows an active feedback loop comprising the laser, a splitter, a frequency discriminator and a photodetector. There is not shown an amplifier and a vector sum module. Ackerman shows in Fig. 1 a similar feedback system for tuning a tunable laser for wavelength stabilization. The feedback loop includes the laser 12, splitter 22, frequency discriminator 16, photodetector 16.1-.2, amplifier 24, and vector sum module where 26 and 28 are summed. Fig. 1, col. 3 line 4 to col. 4 line 14. It would have been obvious to a person of ordinary skill in the art to use Ackerman’s feedback system, including the claimed parts, as it provides for a stable wavelength, avoiding noise due to drift caused by aging or defects, as taught by Ackerman. Col. 3 lines 28-40. Additionally this could be considered a simple substitution of one known element for another to yield predictable results. MPEP 2143 I.B. This is a substitution of Ackerman’s feedback system for Bobbs’ system. The result of the substitution would have been predictable as Ackerman explains how its system works, many of the parts are the same, and the point of both is substantially the same, to provide a stable wavelength output in a tunable laser by using feedback for controlling a current to the electrodes.
Regarding claim 16, each of Bobbs and Ackerman provides a feedback signal to the electrodes as it provides a bias/tuning current controller as part of the feedback system.
Other Pertinent Art
Note that the examiner agrees with the EPO, see 8/6/2024 IDS, that rejections could also be made based on Mori or US 4,802,187 to Bouley et al.
WO 2017/220144 describes a DFB laser having multiple contacts and the grating and waveguide section may have varying width along its length. See e.g. Fig. 12.
US 6,301,283 discloses a DFB laser having separate top electrodes over a tapered (i.e. varying in width) ridge waveguide. Fig. 8.
US 6,411,640 discloses a DFB laser having separate top electrodes over a waveguide that may vary in width. Fig. 8A-B.
Any of these could likely also support rejections of many of the claims.
Conclusion
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/JAMES A MENEFEE/Primary Examiner, Art Unit 2828