US5044715A
Expired / Lapsed
US
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Guided-wave optical branching components and optical switches
Assignee: NTT Inc
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Filing: 1990-02-05
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Granted: 1991-09-03
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Expires: 2010-02-05
Abstract
Abstract A guided-wave optical branching component is composed of a Mach-Zehnder interferometer having two or more directional couplers. A slight difference ΔL in the optical-path length is provided in two or more optical waveguides connecting the two or more directional couplers. The difference of the optical-path length is less than the shortest wavelength in the operational wavelength region of the guided-wave optical branching component, and the coupling ratio of each of the two directional couplers monotonically increases with wavelength in the operational wavelength region. By using the optical branching components thus constructed (i.e., Mach-Zehnder interferometer type 3-dB optical coupler) in conjunction with a phase shifter, a Mach-Zehnder interferometer type optical switch can be achieved.
Inventors
- 👤 Masao Kawachi
- 👤 Kaname Jinguji
- 👤 Norio Takato
- 👤 Akihiro Takagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:27
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/12007; G02B6/12004; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2856; G02B6/30; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3136; G02B2006/2865; G02B6/293; G02B6/29346; G02B6/2935; G02B6/29352; G02B6/29355; G02B6/29379; G02B6/29395
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
132 words
A guided-wave optical branching component having two or more optical waveguides, said optical waveguides being in proximity with one another at a plurality of positions so as to constitute a plurality of directional couplers, one end of each said optical waveguides being an input port and the other end of each said optical waveguides being an output port, wherein the effective optical-path length of at least one of said optical waveguides differs from that of the other optical waveguides between two arbitrarily selected adjacent directional couplers, the difference of said effective optical-path length being less than the shortest wavelength in the operational wavelength region of said guided-wave optical branching component, the coupling ratio of each of said two adjacent directional couplers monotonically increases according to the wavelength in said operational wavelength region.
Claim 2
Dependent Claim
132 words
A guided-wave optical branching component having two or more optical waveguides, said optical waveguides being in proximity with one another at a plurality of positions so as to constitute a plurality of directional couplers, one end of each said optical waveguides being an input port and the other end of each said optical waveguides being an output port, wherein the effective optical-path length of at least one of said optical waveguides differs from that of the other optical waveguides between two arbitrarily selected adjacent directional couplers, the difference of said effective optical-path length being less than the shortest wavelength in the operational wavelength region of said guided-wave optical branching component, the coupling ratio of each of said two adjacent directional couplers monotonically increases according to the wavelength in said operational wavelength region.
Claim 3
Dependent Claim
21 words
A guided-wave optical branching component according to claim 1 wherein said two or more optical waveguides are placed on a substrate.
Claim 4
Dependent Claim
21 words
A guided-wave optical branching component according to claim 1 wherein said two or more optical waveguides are composed of optical fibers.
Claim 5
Dependent Claim
25 words
A guided-wave optical branching component according to claim 1 wherein said guided-wave optical branching component is provided with two input ports and two output ports.
Claim 6
Dependent Claim
25 words
A guided-wave optical branching component according to claim 1 wherein said guided-wave optical branching component is provided with three input ports and three output ports.
Claim 7
Dependent Claim
24 words
A guided-wave optical branching component according to claim wherein said coupling ratios of said two adjacent directional couplers are set different from each other.
Claim 8
Dependent Claim
25 words
A guided-wave optical branching component according to claim 2 wherein said coupling ratios of said two adjacent directional couplers are set different from each other.
Claim 9
Dependent Claim
25 words
A guided-wave optical branching component according to claim 3 wherein said coupling ratios of said two adjacent directional couplers are set different from each other.
Claim 10
Dependent Claim
25 words
A guided-wave optical branching component according to claim 4 wherein said coupling ratios of said two adjacent directional couplers are set different from each other.
Claim 11
Dependent Claim
25 words
A guided-wave optical branching component according to claim 5 wherein said coupling ratios of said two adjacent directional couplers are set different from each other.
Claim 12
Dependent Claim
54 words
A guided-wave optical branching component according to claim 1 wherein said guided-wave optical branching component comprises an optical phase shifter for fine adjusting the effective optical-path length between said adjacent directional couplers, said optical phase shifter being placed on at least one of said two or more optical waveguides connecting said adjacent directional couplers.
Claim 13
Dependent Claim
54 words
A guided-wave optical branching component according to claim 2 wherein said guided-wave optical branching component comprises an optical phase shifter for fine adjusting the effective optical-path length between said adjacent directional couplers, said optical phase shifter being placed on at least one of said two or more optical waveguides connecting said adjacent directional couplers.
Claim 14
Dependent Claim
195 words
A guided-wave optical switch having two optical waveguides, primary and secondary 3-dB optical coupling members, and an optical phase shifter, each of said primary and secondary 3-dB optical coupling members coupling said two optical waveguides at different positions, said optical phase shifter being placed on said optical waveguides between said primary and secondary 3-dB optical coupling members so as to fine adjust the optical-path length of said optical waveguides, wherein: each of said primary and secondary 3-dB optical coupling members has two directional couplers formed by bringing said two optical waveguides into close proximity at different positions; the effective optical-path length of one of said optical waveguides differs from that of the other optical waveguide between said two directional couplers, the difference of said effective optical-path length is less than the shortest wavelength in the predetermined operational wavelength region and the coupling ratio of each of said two directional couplers monotonically increases with wavelength in said operational wavelength region; and the optical waveguide having a longer optical-path length in the primary 3-dB optical coupling member, and the optical waveguide having a longer optical-path length in the secondary 3-dB optical coupling member are different optical waveguides.
Claim 15
Dependent Claim
195 words
A guided-wave optical switch having two optical waveguides, primary and secondary 3-dB optical coupling members, and an optical phase shifter, each of said primary and secondary 3-dB optical coupling members coupling said two optical waveguides at different positions, said optical phase shifter being placed on said optical waveguides between said primary and secondary 3-dB optical coupling members so as to fine adjust the optical-path length of said optical waveguides, wherein: each of said primary and secondary 3-dB optical coupling members has two directional couplers formed by bringing said two optical waveguides into close proximity at different positions; the effective optical-path length of one of said optical waveguides differs from that of the other optical waveguide between said two directional couplers, the difference of said effective optical-path length is less than the shortest wavelength in the predetermined operational wavelength region and the coupling ratio of each of said two directional couplers monotonically increases with wavelength in said operational wavelength region; and the optical waveguide having a longer optical-path length in the primary 3-dB optical coupling member, and the optical waveguide having a longer optical-path length in the secondary 3-dB optical coupling member are different optical waveguides.
Claim 16
Dependent Claim
18 words
A guided-wave optical switch according to claim 13 wherein said two optical waveguides are placed on a substrate.
Claim 17
Dependent Claim
18 words
A guided-wave optical switch according to claim 13 wherein said two optical waveguides are composed of optical fibers.
Claim 18
Dependent Claim
62 words
A guided-wave optical switch according to claim 13 wherein said coupling ratios of said two directional couplers are set different from each other, and the coupling region of said primary 3-dB optical coupling member and the coupling region of said secondary 3-dB optical coupling member are arranged substantially symmetrically with regard to the central point between said two 3-dB optical coupling members.
Claim 19
Dependent Claim
63 words
A guided-wave optical branching component according to claim 14 wherein said coupling ratios of said two directional couplers are set different from each other, and the coupling region of said primary 3-dB optical coupling member and the coupling region of said secondary 3-dB optical coupling member are arranged substantially symmetrically with regard to the central point between said two 3-dB optical coupling members.
Claim 20
Dependent Claim
63 words
A guided-wave optical branching component according to claim 15 wherein said coupling ratios of said two directional couplers are set different from each other, and the coupling region of said primary 3-dB optical coupling member and the coupling region of said secondary 3-dB optical coupling member are arranged substantially symmetrically with regard to the central point between said two 3-dB optical coupling members.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-09-02 | 1995-03-04 | 1995-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-02 | 1999-03-04 | 1999-09-03 | $3760.00 | Window Closed / Lapsed |
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