US5881199A
Expired / Lapsed
US
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Optical branching device integrated with tunable attenuators for system gain/loss equalization
Assignee: Agere Systems LLC
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Filing: 1996-12-02
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Granted: 1999-03-09
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Expires: 2016-12-02
Abstract
Abstract A dense waveguide division multiplexer (DWDM) is integrated on a single chip with a plurality of tunable attenuators that are connected in series to the output waveguides of the DWDM in order to equalize the power level on the output waveguides. In the preferred embodiment, the attenuators are thermo-optic Mach-Zehnder interferometer (TMZs) with a tunable range of 0 to 6 dB and a response time of approximately 1-10 milliseconds (ms). A heat sink is attached to the back of the chip to dissipate the heat from the TMZs and to reduce thermal crosstalk. In order to achieve a 3 dB loss on one of the output waveguides via the corresponding TMZ attenuator, approximately 0.25 W is required. In an alternative embodiment, the attenuators are variable stress Mach-Zehnder interferometers (VSMZs).
Inventors
- 👤 Yuan P. Li
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:38
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/12007; G02B6/12009; G02B6/12016; G02B6/12033; G02B6/122; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/01; G02F1/0128; G02F1/0131; G02F1/0134; G02F1/0147; G02F1/21; G02F1/212; G02F2203/00; G02F2203/48
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
107 words
An integrated optical waveguide device, comprising: an optical branching device fabricated on a substrate and having a plurality of ports; and an attenuator integrated with said optical branching device on said substrate and connected to a first one of said ports, said attenuator being substantially tunable over a continuum ranging from optical transparency to optical opaqueness; controlling means for adjusting an attenuation applied to an optical signal on said first one of said ports by said attenuator, said controlling means being responsive to a power level of said optical signal and said attenuator being responsive to an attenuation adjustment signal from said controlling means in real time.
Claim 2
Dependent Claim
107 words
An integrated optical waveguide device, comprising: an optical branching device fabricated on a substrate and having a plurality of ports; and an attenuator integrated with said optical branching device on said substrate and connected to a first one of said ports, said attenuator being substantially tunable over a continuum ranging from optical transparency to optical opaqueness; controlling means for adjusting an attenuation applied to an optical signal on said first one of said ports by said attenuator, said controlling means being responsive to a power level of said optical signal and said attenuator being responsive to an attenuation adjustment signal from said controlling means in real time.
Claim 3
Dependent Claim
26 words
The waveguide device of claim 1, wherein said optical branching device is a dense waveguide division multiplexer having a plurality of interconnected input and output waveguides.
Claim 4
Dependent Claim
15 words
The waveguide device of claim 2, wherein said tunable attenuator comprises a thermo-optic Mach-Zehnder interferometer.
Claim 5
Dependent Claim
38 words
The waveguide device of claim 3, wherein said thermo-optic Mach-Zehnder interferometer includes a first optical coupler and a second optical coupler linked by two waveguide arms, and a heater associated with at least one of said waveguide arms.
Claim 6
Dependent Claim
45 words
The waveguide device of claim 4, wherein said thermo-optic Mach-Zehnder interferometer includes an electrode adjacent each of said optical couplers and connected to said heater for actuating said heater, and wherein said electrodes and said heater are formed from a same layer of conductive material.
Claim 7
Dependent Claim
63 words
The waveguide device of claim 3, wherein said thermo-optic Mach-Zehnder interferometer includes first and second input waveguides and first and second output waveguides, and wherein said first output waveguide of said dense waveguide division multiplexer is connected to said first input waveguide of said interferometer, and wherein said attenuated optical signal is provided on said first output waveguide of said thermo-optic Mach-Zehnder interferometer.
Claim 8
Dependent Claim
16 words
The waveguide device of claim 2, wherein said tunable attenuator comprises a variable stress Mach-Zehnder interferometer.
Claim 9
Dependent Claim
34 words
The waveguide device of claim 7, wherein said variable stress Mach-Zehnder interferometer includes a layer of piezo-electric material that is actuated by two electrodes and is positioned adjacent to one of said output waveguides.
Claim 10
Dependent Claim
90 words
The waveguide device of claim 2, further comprising: a plurality of attenuators integrated with said dense waveguide division multiplexer on said substrate and connected to respective said output waveguides, said attenuators being substantially tunable over a continuum ranging from optical transparency to optical opaqueness and being responsive to an attenuation adjustment signal from said controlling means in real time; and said controlling means adjusting an attenuation applied to an optical signal on each said output waveguide, said controlling means being responsive to a power level of each said optical signal.
Claim 11
Dependent Claim
18 words
The waveguide device of claim 2, wherein said tunable attenuator has a tunable attenuation range of 6 dB.
Claim 12
Dependent Claim
30 words
The waveguide device of claim 2, wherein said tunable attenuator comprises two Y-branches interconnected by two waveguide arms and a beater associated with at least one of said waveguide arms.
Claim 13
Dependent Claim
102 words
An integrated optical waveguide device, comprising: a dense waveguide division multiplexer having a plurality of interconnected input and output waveguides, said output waveguides having respective optical signals of different strengths; and a plurality of thermo-optic Mach-Zehnder interferometers having first and second waveguides interfacing at first and second coupler regions, wherein said output waveguides of said dense waveguide division multiplexer are connected to respective said thermo-optic Mach-Zehnder interferometers, each said thermo-optic Mach-Zehnder interferometer configured for selectively and controllably attenuating said respective optical signal of each said output waveguide of said dense waveguide division multiplexer so as to substantially equalize said optical signal strengths.
Claim 14
Dependent Claim
102 words
An integrated optical waveguide device, comprising: a dense waveguide division multiplexer having a plurality of interconnected input and output waveguides, said output waveguides having respective optical signals of different strengths; and a plurality of thermo-optic Mach-Zehnder interferometers having first and second waveguides interfacing at first and second coupler regions, wherein said output waveguides of said dense waveguide division multiplexer are connected to respective said thermo-optic Mach-Zehnder interferometers, each said thermo-optic Mach-Zehnder interferometer configured for selectively and controllably attenuating said respective optical signal of each said output waveguide of said dense waveguide division multiplexer so as to substantially equalize said optical signal strengths.
Claim 15
Dependent Claim
17 words
The device of claim 12, wherein at least one of said thermo-optic Mach-Zehnder interferometers comprises four ports.
Claim 16
Dependent Claim
17 words
The device of claim 12, wherein at least one of said thermo-optic Mach-Zehnder interferometers comprises two ports.
Claim 17
Independent Claim
110 words
A method of fabricating a dense waveguide division multiplexer having a plurality of input and output waveguides so that the power of the optical signals at the output waveguides are substantially equal, comprising the steps of: fabricating said dense waveguide division multiplexer on a silicon-based substrate; fabricating a plurality of attenuators on said substrate adjacent to said dense waveguide division multiplexer, wherein each said attenuator is connected to a respective one of said waveguide outputs of said dense waveguide division multiplexer, said attenuators being substantially tunable over a continuum ranging from optical transparency to optical opaqueness and being responsive to an attenuation adjustment signal from controlling means in real time.
Claim 18
Independent Claim
110 words
A method of fabricating a dense waveguide division multiplexer having a plurality of input and output waveguides so that the power of the optical signals at the output waveguides are substantially equal, comprising the steps of: fabricating said dense waveguide division multiplexer on a silicon-based substrate; fabricating a plurality of attenuators on said substrate adjacent to said dense waveguide division multiplexer, wherein each said attenuator is connected to a respective one of said waveguide outputs of said dense waveguide division multiplexer, said attenuators being substantially tunable over a continuum ranging from optical transparency to optical opaqueness and being responsive to an attenuation adjustment signal from controlling means in real time.
Claim 19
Dependent Claim
13 words
The method of claim 15, wherein said tunable attenuators comprise thermo-optic Mach-Zehnder interferometers.
Claim 20
Dependent Claim
14 words
The method of claim 15, wherein said tunable attenuators comprise variable stress Mach-Zehnder interferometers.
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| 3.5 Years (Year 4) | 2002-03-08 | 2002-09-07 | 2003-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-08 | 2006-09-07 | 2007-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-08 | 2010-09-07 | 2011-03-09 | $7700.00 | Window Closed / Lapsed |