Detailed Office 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 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.
Examiner’s Comment – Independent Claims 1 and 19
Independent claims 1 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Prosyk, Kelvin (2013/0163913; “Prosyk”) in view of Khharel et al. (2021/0157177; “Kharel”).
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 of this title, 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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-4, 16-17, 19 and 20
Claims 1-4, 16-17, 19 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Prosyk, Kelvin (2013/0163913; “Prosyk”) in view of Khharel et al. (2021/0157177; “Kharel”).
Regarding claim 1, Prosyk discloses in figure 12, and related figures and text, for example, Prosyk – Selected Text, optical modulator embodiments 10 disclosing two signal electrode channels with T-shaped lateral extensions (shown but not labeled) acting on the two arms of Mach-Zehnder modulators (shown but not labeled and two ground electrodes (shown but not labeled) associated with the signal electrodes, arranged laterally as first ground electrode, first signal electrode, first waveguide, second waveguide, second signal electrode, and second ground electrodes. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text.
Prosyk – Figure 12
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Prosyk – Selected Text
Abstract. An electrical waveguide transmission device accepts a differential electrical input signal (e.g., S+ and S-) propagating along two separate signal conductors with grounded electrical return paths, and outputs the differential input signal to a series push-pull traveling wave electrode Mach-Zehnder optical modulator over a pair of output conductors that act as a return path for each other and provide a desired characteristic impedance matching that of the Mach-Zehnder optical modulator.
[0015] This invention provides an electrical waveguide transmission device that accepts a differential electrical input signal (e.g., S+ and S-) propagating along two separate signal conductors with grounded electrical return paths, and outputs the differential input signal to a series push-pull traveling wave electrode Mach-Zehnder modulator over a pair of output conductors that act as a return path for each other (i.e., without the need for a grounded conductor) and provide a desired characteristic impedance matching that of the Mach-Zehnder modulator.
[0016] In particular, the two input signal conductors of the electrical waveguide transmission device have at least one input ground conductor interposed between them. This configuration of input signal conductors and input ground conductors forms a first waveguide between the first input signal conductor and a ground conductor having a first characteristic impedance, and also forms a second waveguide between the second input signal conductor and a ground conductor having a second characteristic impedance. The differential input signal is output via two output signal conductors that have no ground conductor interposed between them. These output signal conductors form a third waveguide having a third characteristic impedance that is the sum of the first and second characteristic impedances, and is also equal to the characteristic impedance of the Mach-Zehnder traveling wave electrode.
[0047] FIG. 12 is a schematic diagram of the electrical waveguide transmission device 15 of FIG. 11 in a configuration with a differential drive 20 at the input, and a GSSG series push-pull Mach-Zehnder optical modulator 10 with a matching terminating load 30 in the preferred embodiment. For example, the driver output impedance of Z1 equals 50 ohms; the driver complementary output impedance of Z2 equals 50 ohms; and the distal load impedance of Z3 equals 100 ohms. FIG. 13 is a graph showing the simulated fraction of power delivered to the distal load (S21), and reflected back to the driver (S11) in this example embodiment of FIG. 12. Note that excellent broadband performance is possible using this embodiment of the present invention.
Further regarding claim 1, Kharel discloses in figures 23 and 24, and related figures and text, for example, Kharel – Selected Text, embodiments of optical modulators in which first signal electrode extensions are arranged to be laterally interlaced second signal electrode extensions and first signal electrode extensions and second signal electrode extensions are arranged to be laterally interlaced with first and second waveguides, respectively. Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
Kharel – Figures 23 and 24
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Kharel – Selected Text
[0002] Optical modulators and other electro-optic devices are generally desired to meet certain performance benchmarks. For example, an optical modulator is desired to be capable of providing a sufficient optical modulation at lower electrode driving voltages. A large optical modulation may correspond to the waveguide having a large length in the direction of transmission of the optical signal. However, the optical modulator is also desired to consume a small total area. The optical modulator is also desired to have low electrode (e.g. microwave) signal losses for the electrical signal through the electrodes and low optical losses for the optical signal traversing the waveguide. Further, the optical modulators are desired to be capable of providing the low loss transmission and large modulation at low voltages over a wide bandwidth of frequencies. Therefore, an electro-optic device that may have low electrode losses, low optical losses, consume a controlled amount of area, and/or provide the desired optical modulation at low voltages is desired.
[0137] FIG. 23 depicts a plan view of a portion of optical device 2300. Optical device 2300 is analogous to optical device(s) 100, 100′, 100″, 100′″ and/or 100′″. Consequently, similar structures have analogous labels. Optical device 2300 including waveguides 2310 and 2350 (e.g. arms of a waveguide) as well as electrodes 2320 and 2330 that are analogous to waveguides 110′ and 150 and electrodes 120 and 130, respectively. Electrodes 2320 and 2330 include channel portions 2322 and 2332, respectively, as well as extensions 2324 and 2334 that are analogous to channel portions 122, 132 and 142 and extensions 224, 234 and 244. As can be seen in FIG. 23, extensions 2334 and 2324 include metal bridges extending over the top of waveguides 2310 and 2350 to locate extensions 2324 and 2334 such that the field on waveguide 2310 and 2350 is more symmetric. Optical device 2300 may share the benefits of optical device(s) 100, 100′, 100″, and 100′″.
[0138] FIG. 24 depicts a plan view of a portion of optical device 2400. Optical device 2400 is analogous to optical device(s) 100, 100′, 100″, 100′″ and/or 100′″. Consequently, similar structures have analogous labels. Optical device 2400 including waveguides 2410 and 2450 as well as electrodes 2420 and 2430 that are analogous to waveguides 110′ and 150 and electrodes 120 and 130, respectively. Electrodes 2420 and 2430 include channel portions 2422 and 2432, respectively, as well as extensions 2424 and 2434 that are analogous to channel portions 122 and 132 and extensions 224 and 234. As can be seen in FIG. 24, extensions 2434 and 2424 include metal bridges extending over the top of waveguides 2410 and 2550 as well as additional retrograde features to locate and configure extensions 2424 and 2434 such that the field on waveguides 2410 and 2450 is more symmetric.
[0139] More specifically, in order to induce opposite shifts on the waveguides 2410 and 2450, the extensions 2424 and 2434 are connected with opposite polarity by first positive metal bridges extending over the top of waveguides 2450 and 2410, respectively. The metal bridges connect the retrograde portions of extensions 2424 and 2434 with channel regions 2422 and 2432, respectively, while inducing minimal optical losses in waveguides 2410 and 2450. In addition a second set of retrograde portions for the extensions 2424 and 2434 are provided on an opposite side of the waveguides 2410 and 2450 so that the geometry of optical device 2400 is symmetric. Optical device 2400 has less modulator chirp (difference in modulation strength in two waveguides 2410 and 2450) than optical device 2300, at the cost of increased design complexity and possibly reduced microwave bandwidth. Optical device 2400 may share the benefits of optical device(s) 100, 100′, 100″, and 100′″.
Consequently, it would have been obvious to one of ordinary skill in the art to modify Prosyk’s embodiments to comprise: an optical splitter configured to split an optical input signal into a first optical signal and a second optical signal; a first optical waveguide and a second optical waveguide, wherein the first optical waveguide and the second optical waveguide are configured to provide optical transmission paths for the first optical signal and the second optical signal, respectively; traveling wave electrodes extending along a first direction and configured to transmit a radio frequency signal, wherein the traveling wave electrodes comprise a first grounding electrode, a first signal electrode, a second signal electrode, and a second grounding electrode, wherein the first grounding electrode, the first signal electrode, the second signal electrode, and the second grounding electrode are arranged in sequence in a second direction, and the second direction intersects the first direction; and extension electrodes arranged along the optical transmission paths in a gap between the first signal electrode and the second signal electrode and configured to modulate the first optical signal and the second optical signal based on the radio frequency signal, wherein the extension electrodes comprise at least one first signal sub-electrode and two second signal sub-electrodes, wherein the at least one first signal sub-electrode and the two second signal sub-electrodes are arranged side by side in the second direction and each has a length direction parallel to the first direction, the two second signal sub-electrodes are arranged on both sides of the at least one first signal sub-electrode, the first optical waveguide is arranged between one second signal sub-electrode of the two second signal sub-electrodes and a first signal sub-electrode adjacent to the one second signal sub-electrode, and the second optical waveguide is arranged between the other second signal sub-electrode of the two second signal sub-electrodes and a first signal sub-electrode adjacent to the other second signal sub-electrode, and the first signal electrode is electrically connected to the first signal sub-electrodes, and the second signal electrode is electrically connected to the second signal sub-electrodes; Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; because the resulting configuration would facilitate designing, fabricating, and deploying low-footprint, high-symmetry ‘electro-optic devices characterized by low electrode losses, low optical losses, low voltage, and/or optimized optical modulation.’ Kharel – Selected Text.
Regarding dependent claims 2-4 and 16-17, it would have been obvious to one of ordinary skill in the art to modify Prosyk in view of Kharel’s embodiments, as applied in the rejection of claim 1, to disclose:
2. The electro-optic modulator according to claim 1, further comprising first extension arms and second extension arms, wherein the first extension arms and the second extension arms are respectively configured to electrically connect the first signal electrode to the first signal sub-electrode and the second signal electrode to the second signal sub-electrodes. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
3. The electro-optic modulator according to claim 1, wherein positions of the electrical connections cause each of the first signal sub-electrode and the second signal sub-electrodes to be divided into one or more sections in the first direction. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
4. The electro-optic modulator according to claim 2, wherein the first extension arms and the second extension arms cause the first signal sub-electrode and the second signal sub-electrodes to be divided by the first extension arms and the second extension arms respectively into one or more sections in the first direction. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
16. The electro-optic modulator according to claim 1, further comprising an optical combiner configured to combine the first optical signal and the second optical signal into an optical output signal. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
17. The electro-optic modulator according to claim 1, wherein the first optical waveguide and the second optical waveguide are lithium niobate optical waveguides. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
because the resulting configurations would facilitate designing, fabricating, and deploying low-footprint, high-symmetry ‘electro-optic devices characterized by low electrode losses, low optical losses, low voltage, and/or optimized optical modulation.’Kharel – Selected Text.
Regarding dependent claims 19 and 20, it would have been obvious to one of ordinary skill in the art to modify Prosyk in view of Kharel’s embodiments, as applied in the rejection of claims 1-4 and 16-17, to disclose:
19. An electro-optic device, comprising an electro-optic modulator, wherein the electro-optic modulator comprises: an optical splitter configured to split an optical input signal into a first optical signal and a second optical signal; a first optical waveguide and a second optical waveguide, wherein the first optical waveguide and the second optical waveguide are configured to provide optical transmission paths for the first optical signal and the second optical signal, respectively; traveling wave electrodes extending along a first direction and configured to transmit a radio frequency signal, wherein the traveling wave electrodes comprise a first grounding electrode, a first signal electrode, a second signal electrode, and a second grounding electrode, wherein the first grounding electrode, the first signal electrode, the second signal electrode, and the second grounding electrode are arranged in sequence in a second direction, and the second direction intersects the first direction; and extension electrodes arranged along the optical transmission paths in a gap between the first signal electrode and the second signal electrode and configured to modulate the first optical signal and the second optical signal based on the radio frequency signal, wherein the extension electrodes comprise at least one first signal sub-electrode and two second signal sub-electrodes, wherein the at least one first signal sub-electrode and the two second signal sub-electrodes are arranged side by side in the second direction and each has a length direction parallel to the first direction, the two second signal sub-electrodes are arranged on both sides of the at least one first signal sub-electrode, the first optical waveguide is arranged between one second signal sub-electrode of the two second signal sub-electrodes and a first signal sub-electrode adjacent to the one second signal sub-electrode, and the second optical waveguide is arranged between the other second signal sub-electrode of the two second signal sub-electrodes and a first signal sub-electrode adjacent to the other second signal sub-electrode, and the first signal electrode is electrically connected to the first signal sub-electrodes, and the second signal electrode is electrically connected to the second signal sub-electrodes. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
20. The electro-optic device according to claim 19, wherein electro-optic modulator comprises first extension arms and second extension arms, wherein the first extension arms and the second extension arms are respectively configured to electrically connect the first signal electrode to the first signal sub-electrode and the second signal electrode to the second signal sub-electrodes. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text.
because the resulting configurations would facilitate designing, fabricating, and deploying low-footprint, high-symmetry ‘electro-optic devices characterized by low electrode losses, low optical losses, low voltage, and/or optimized optical modulation.’Kharel – Selected Text.
Claims 5-13 and 18
Claims 5-13 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Prosyk, Kelvin (2013/0163913; “Prosyk”) in view of Khharel et al. (2021/0157177; “Kharel”), as applied in the rejection of claims 1-4, 16-17, 19 and 20, and further in view of Yagi et al. (20160026063; “Yagi”).
Regarding claims 5-13 and 18, Yagi discloses in figures 1-11, and related text, for example, Yagi – Selected Text, optical modulator embodiments having protective layers, for example, “The first insulating layer 41 covers the substrate 10 and the arm waveguide 23b. The first resin layer 42, the second insulating layer 43, the second resin layer 44, and the third insulating layer 45 are stacked on the first insulating layer 41 in that order.” Yagi, paragraph [0032].
Yagi – Selected Text
Abstract. A modulator including: a Mach-Zehnder modulator that includes an optical waveguide disposed on a substrate, the optical waveguide including an electrode thereon; a resin layer disposed on the substrate, the resin layer embedding the optical waveguide, the resin layer having a groove arranged besides the optical waveguide; a termination resistor disposed on the substrate in the groove of the resin layer; and a first wiring disposed on the resin layer, the first wiring being connected to the termination resistor and the electrode of the optical waveguide.
[0022] A resin layer is disposed on the substrate 10. The resin layer covers a surface of the substrate 10, and the resin layer embeds the optical waveguides of the Mach-Zehnder modulator. The resin layer has grooves formed therein. A termination resistor 50a is disposed on the substrate in one groove. A termination resistor 50b is disposed on the substrate in another groove.
[0032] The first insulating layer 41 covers the substrate 10 and the arm waveguide 23b. The first resin layer 42, the second insulating layer 43, the second resin layer 44, and the third insulating layer 45 are stacked on the first insulating layer 41 in that order. The first insulating layer 41 is, for example, composed of SiO.sub.2. The first resin layer 42 is, for example, composed of a resin such as bis-benzocyclobutene (BCB). The second insulating layer 43 is, for example, composed of SiO.sub.2. The second resin layer 44 is, for example, composed of a resin such as BCB. The third insulating layer 45 is, for example, composed of SiO.sub.2. The arm waveguide 23a (not shown in FIG. 3) has a similar structure with the arm waveguide 23b. The arm waveguide 23a is also embedded by the first resin layer 42.
[0033] The resistor 50b is in contact with and disposed on the first insulating layer 41 in a region where the optical waveguides of the Mach-Zehnder modulator are not formed. Specifically, the resistor 50b is disposed on the substrate 10 with the first insulating layer 41 therebetween. The resistor 50b is located in a groove formed in the first resin layer 42. The resistor 50b is embedded by the second resin layer 44. The resistor 50b is, for example, a NiCrSi thin film. An upper surface of the resistor 50b is covered with the second resin layer 44. The resistor 50a (not shown in FIG. 3) has a similar structure with the resistor 50b.
[0037] The second resin layer 44 covers the resistors 50a and 50b. The resin layer on the resistors protects the resistors from a damage. In addition, as the resin layer is disposed on the resistors, heat dissipation from the resistor is smoother compared to when the upper surfaces of the resistors are in contact with air.
Consequently, in light of Yagi’s disclosure of embodiments protective layer configurations, it would have been obvious to one of ordinary skill in the art to modify Prosyk in view of Kharel’s embodiments, as applied in the rejection of claims 1-4 and 16-17, to disclose:
5. The electro-optic modulator according to claim 1, further comprising: a substrate; an isolating layer located on the substrate; a thin film layer configured to form the first optical waveguide and the second optical waveguide; and a covering layer located on the first optical waveguide and the second optical waveguide. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
6. The electro-optic modulator according to claim 5, wherein the covering layer extends to other areas on the thin film layer than the first optical waveguide and the second optical waveguide. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
7. The electro-optic modulator according to claim 5, wherein at least some of the traveling wave electrodes and at least some of the extension electrodes are located in the isolating layer. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
8. The electro-optic modulator according to claim 5, wherein the traveling wave electrodes and the extension electrodes are located on the isolating layer. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
9. The electro-optic modulator according to claim 5, wherein at least two of the traveling wave electrodes and at least two of the extension electrodes are located in the thin film layer. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
10. The electro-optic modulator according to claim 5, wherein the traveling wave electrodes and the extension electrodes are located on the thin film layer. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
11. The electro-optic modulator according to claim 5, wherein the traveling wave electrodes are located on the thin film layer, and the extension electrodes are located on the covering layer. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
12. The electro-optic modulator according to claim 6, wherein the traveling wave electrodes are located on the covering layer over the other areas, and the extension electrodes are located on the covering layer over the first optical waveguide and the second optical waveguide. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
13. The electro-optic modulator according to claim 6, wherein the traveling wave electrodes and the extension electrodes are located on the covering layer over the other areas. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
18. The electro-optic modulator according to claim 1, further comprising a protective layer configured to cover at least one element. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text.
because the resulting configurations would facilitate designing, fabricating, and deploying low-footprint, high-symmetry ‘electro-optic devices characterized by low electrode losses, low optical losses, low voltage, and/or optimized optical modulation;’ Kharel – Selected Text; and characterized by mechanical protection and thermal/electrical insulation. Yagi – Selected Text.
Claims 14 and 15
Claims 14 and15 are rejected under 35 U.S.C. 103 as being unpatentable over Prosyk, Kelvin (2013/0163913; “Prosyk”) in view of Khharel et al. (2021/0157177; “Kharel”), as applied in the rejection of claims 1-4, 16-17, 19 and 20, and further in view of Yagi et al. (20160026063; “Yagi”), as applied in the rejection of claims 5-13 and 18, and further in view of Velthaus, Karl-Otto (2015/0043865; “Velthaus”).
Regarding claims 14 and 15, Velthaus discloses in figures 1-6, and related figures and text, for example, Velthaus – Selected Text, optical modulator embodiments ‘wherein the p-doped layer can be removed between adjacent capacitive segments (the active sections of the waveguides) in order to electrical isolate the active sections from each other and reduce the optical loss in the waveguide sections between the capacitive segments (i.e. in the passive sections of the waveguides). Velthaus – Selected Text.
Velthaus – Selected Text
Abstract. A Mach-Zehnder modulator arrangement includes at least one electro-optic Mach-Zehnder modulator having a first optical waveguide forming a first modulator arm and a second optical waveguide forming a second modulator arm. A travelling wave electrode arrangement includes first waveguide electrodes for applying a voltage across the first optical waveguide and second waveguide electrodes for applying a voltage across the second optical waveguide. The first waveguide electrodes are capacitively coupled to the second waveguide electrodes. A driver unit supplies an alternating voltage to the travelling wave electrode arrangement. The driver unit includes a first output port coupled to the first waveguide electrodes and a second output port coupled to the second waveguide electrodes. The driver unit supplies a first varying signal to the first waveguide electrodes via the first output port and a second varying signal to the second waveguide electrodes via the second output port.
[0033] For example, the Mach-Zehnder modulator of the arrangement according to the invention is formed as a semi-conductor device, wherein the conductive region is formed by an n-doped semiconductor layer. In particular, the Mach-Zehnder modulator is fabricated using indium phosphide or gallium arsenide technology, i.e. the modulator is fabricated on an indium phosphide or a gallium arsenide substrate. For example, the capacitive segments of the modulator arms comprise a p-doped layer, wherein the p-doped layer can be removed between adjacent capacitive segments (the active sections of the waveguides) in order to electrical isolate the active sections from each other and reduce the optical loss in the waveguide sections between the capacitive segments (i.e. in the passive sections of the waveguides).
[0034] The p-doped layer in the capacitive segments may form part of a p-i-n-diode, wherein the isolating region of the p-i-n-diode is formed by at least one isolating layer arranged between the p-doped layer and an n-doped layer or an n-doped substrate. It is, however, also possible that other kinds of diodes realize the capacitive segments such as n-i-n diodes and/or Schottky diodes.
[0053] The first and second waveguide electrodes 21, 22 are arranged on first and second capacitive segments 111, 121 of the first and the second optical waveguide 11, 12, wherein the capacitive segments 111, 121 are formed by p-i-n diode sections of the optical waveguides 11, 12. An active layer (for example, a multi quantum well layer) forms the intrinsic region, a p-doped region above the intrinsic region the p-region and an n-doped layer below the active layer and arranged on a semi-isolating substrate (e.g. an InP-substrate) the n-region of the diodes.
[0055] The n-doped region 3 is at least partially surrounded by an isolation groove 31 extending through the n-doped layer and thus electrically separating the n-doped region 3 from the coplanar lines 23, 24. For example, the n-doped region 3 has an essentially rectangular contour.
[0068] 1 Mach-Zehnder modulator [0069] 2 Travelling wave electrode arrangement [0070] 3 n-doped region [0071] 4 high frequency source [0072] 5 terminating resistor [0073] 6 DC source [0074] 7 capacitor [0075] 11 first optical waveguide [0076] 12 second optical waveguide [0077] 13, 16 spot size converter [0078] 14 splitter [0079] 15 combiner [0080] 21 first waveguide electrodes [0081] 22 second waveguide electrodes [0082] 23 first coplanar line [0083] 24 second coplanar line [0084] 25 air bridge [0085] 31 isolation groove [0086] 41 driver unit [0087] 42 input port [0088] 43 output port [0089] 44 signal carrying connector [0090] 45 grounded connector [0091] 47, 48 microstrip line [0092] 51 terminating resistor [0093] 111 first capacitive segments [0094] 121 second capacitive segments [0095] 441 first output port [0096] 442 second output port [0097] 451 first signal-carrying connector [0098] 452, 462, 4511, 4611 contact pad [0099] 461 second signal-carrying connector [0100] 471, 481 impedance [0101] 4500 substrate
Consequently, in light of Yagi’s disclosure of embodiments protective layer configurations, it would have been obvious to one of ordinary skill in the art to modify Prosyk in view of Kharel’s embodiments, as applied in the rejection of claims 1-4 and 16-17, and further in view of Yagi, as applied in the rejection of claims 5-13 and 18, to disclose:
14. The electro-optic modulator according to claim 5, wherein the substrate is provided with a groove. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text. Velthaus, figures 1-6, and related figures and text, for example, Velthaus – Selected Text.
15. The electro-optic modulator according to claim 5, wherein the isolating layer is provided with a groove. Prosyk, figure 12, and related figures and text, for example, Prosyk – Selected Text; Kharel, figures 23 and 24, and related figures and text, for example, Kharel – Selected Text; Yagi, figures 1-11, and related text, for example, Yagi – Selected Text. Velthaus, figures 1-6, and related figures and text, for example, Velthaus – Selected Text.
because the resulting configurations would facilitate designing, fabricating, and deploying low-footprint, high-symmetry ‘electro-optic devices characterized by low electrode losses, low optical losses, low voltage, and/or optimized optical modulation;’ Kharel – Selected Text; and characterized by mechanical protection and thermal/electrical insulation; Yagi – Selected Text; provided by removed materials. Velthaus, figures 1-6, and related figures and text, for example, Velthaus – Selected Text.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER RADKOWSKI whose telephone number is (571)270-1613. The examiner can normally be reached on M-Th 9-5. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Thomas Hollweg, can be reached on (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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/PETER RADKOWSKI/Primary Examiner, Art Unit 2874