US4970713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Waveguide type optical multiplexer/demultiplexer with a wave guide regulating function
Assignee: Hitachi Ltd
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Filing: 1988-08-31
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Granted: 1990-11-13
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Expires: 2008-08-31
Abstract
Abstract A waveguide type optical multiplexer/demultiplexer in which a directional coupler made of a three-layer structure wherein core waveguides (refractive index n c : n c >n b ) and a cladding (refractive index n r : n r <n c ) are successively stacked on a low refractive index layer (refractive index n b ), is provided with a thin film heater in or on the cladding, and a voltage is applied across the heater.
Inventors
- 👤 Katsuyuki Imoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:18
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/01; G02F1/011; G02F1/0113; G02F1/0147
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
63 words
A waveguide type optical multiplexer/demultiplexer for two or more signals which have different wavelengths, comprising: a substrate; a low-refractive index layer on the substrate; two core waveguides on the low-refractive index layer, distributively coupling each other; a cladding layer overlaying the core waveguides; and a thin film heater for varying the difference between the refractive indices of the cladding layer and core waveguides.
Claim 2
Dependent Claim
63 words
A waveguide type optical multiplexer/demultiplexer for two or more signals which have different wavelengths, comprising: a substrate; a low-refractive index layer on the substrate; two core waveguides on the low-refractive index layer, distributively coupling each other; a cladding layer overlaying the core waveguides; and a thin film heater for varying the difference between the refractive indices of the cladding layer and core waveguides.
Claim 3
Dependent Claim
22 words
A waveguide type optical multiplexer/demultiplexer according to claim 1, wherein the thin film heater is controlled by temperature of the cladding layer.
Claim 4
Dependent Claim
20 words
A waveguide type optical multiplexer/demultiplexer according to claim 1, wherein the thin film heater is arranged on the cladding layer.
Claim 5
Dependent Claim
20 words
A waveguide type optical multiplexer/demultiplexer according to claim 3, further comprising a protection layer arranged on the thin film heater.
Claim 6
Dependent Claim
108 words
An optical multiplexer/demultiplexer for two or more signals which have different wavelengths, comprising: a plurality of directional couplers each comprising two cores and a cladding, each having a couple of input ports and a couple of output ports, a couple of output ports of one of the directional couplers connecting with the respective inputs of two other directional couplers, each of the directional couplers having a film heater which varies temperature of the coupler by a control signal; and means for providing the control signal for the film heater by detecting an optical signal leaked out at one of the output ports of one of the directional couplers.
Claim 7
Dependent Claim
108 words
An optical multiplexer/demultiplexer for two or more signals which have different wavelengths, comprising: a plurality of directional couplers each comprising two cores and a cladding, each having a couple of input ports and a couple of output ports, a couple of output ports of one of the directional couplers connecting with the respective inputs of two other directional couplers, each of the directional couplers having a film heater which varies temperature of the coupler by a control signal; and means for providing the control signal for the film heater by detecting an optical signal leaked out at one of the output ports of one of the directional couplers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |