Patent US5450511A successfully refreshed from Google Patents.
US5450511A
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Efficient reflective multiplexer arrangement
Assignee: AT&T Inc
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Filing: 1994-07-25
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Granted: 1995-09-12
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Expires: 2014-07-25
Abstract
Abstract The efficiency and freedom from cross-talk achieved by transmissive multiplexer/demultiplexer devices is achieved in a reflective multiplexer/demultiplexer device. The reflective geometry avoids the large size devices necessitated by transmissive geometries handling a large number of optical channels. The reflective geometry also avoids long bends in waveguides used in optical gratings in high efficiency transmissive geometries. Integrated optical multiplexers/demultiplexers in accordance with this invention comprise a plurality of waveguides for carrying unmultiplexed optical signals interleaved with a plurality of waveguides for carrying multiplexed optical signals. The two pluralities of waveguides are connected to the boundary of a free space region. The pluralities of waveguides communicate through the free space region with an optical grating comprising a plurality of waveguides each terminated in a reflective element. The length of each waveguide in the grating differs from the lengths of adjacent waveguides in the grating by a predetermined amount to introduce predetermined path length differences for the optical signals traveling in the waveguides of the grating. Unmultiplexed optical signals, introduced into one or more of the input waveguides for carrying unmultiplexed optical signals, travel through those waveguides into the optical grating and are reflected towards one or more of the output waveguides for carrying multiplexed optical signals. When the device is used as a multiplexer in this fashion, it causes the optical signals introduced into the device to be multiplexed together and appear in a predetermined one or more of the waveguides for carrying multiplexed signals. Multiplexed optical signals introduced into one or more of the waveguides for carrying multiplexed signals are directed through the free space region to the optical grating and are reflected toward one or more of the output waveguides for carrying unmultiplexed optical signals. When the device is used as a demultiplexer in this manner, input signals which comprise a mixture of optical frequencies are demultiplexed so that the individual optical frequencies are separated from one another and appear at one or more predetermined waveguides for carrying unmultiplexed optical signals.
Inventors
- 👤 Corrado Dragone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:59
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/12007; G02B6/12009; G02B6/12011; G02B6/12019
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
107 words
An apparatus, comprising: a first waveguide; a grating comprising a plurality of second waveguides, each of the second waveguides in the grating having two ends and each of the second waveguides in the grating differing in length from each of the other second waveguides in the grating by a predetermined amount; a first end of each of the second waveguides being coupled to the first waveguide so that electromagnetic energy flowing in the first waveguide illuminates a plurality of the first ends of the second waveguides in the grating; and a reflective element connected to a second end of each of the second waveguides in the grating.
Claim 2
Independent Claim
107 words
An apparatus, comprising: a first waveguide; a grating comprising a plurality of second waveguides, each of the second waveguides in the grating having two ends and each of the second waveguides in the grating differing in length from each of the other second waveguides in the grating by a predetermined amount; a first end of each of the second waveguides being coupled to the first waveguide so that electromagnetic energy flowing in the first waveguide illuminates a plurality of the first ends of the second waveguides in the grating; and a reflective element connected to a second end of each of the second waveguides in the grating.
Claim 3
Dependent Claim
18 words
The optical apparatus of claim, 1, in which the at least one reflective element comprises a Bragg reflector.
Claim 4
Dependent Claim
18 words
The optical apparatus of claim 2, in which each of the second plurality of waveguides is substantially straight.
Claim 5
Dependent Claim
36 words
The optical apparatus of claim 1, in which the at least one reflective element comprises an optical diffraction grating attached to an end of at least one of the waveguides in the second plurality of waveguides.
Claim 6
Dependent Claim
36 words
The optical apparatus of claim 1 in which the at least one reflective element comprises an optical diffraction grating machined into an end of at least one of the waveguides in the second plurality of waveguides.
Claim 7
Independent Claim
102 words
A method of multiplexing a plurality of optical wavelengths, comprising the steps of: receiving, in each of a plurality of input waveguides for carrying input optical signals, an optical signal of a predetermined wavelength; directing, through a free space region, the optical signals received in the plurality of waveguides toward a reflective optical grating comprising a plurality of unequal length waveguides each terminated in a reflective element; and reflecting the optical signals directed to the optical grating toward a single one of a plurality of waveguides for carrying multiplexed optical signals interleaved with the plurality of waveguides for carrying unmultiplexed optical signals.
Claim 8
Independent Claim
102 words
A method of multiplexing a plurality of optical wavelengths, comprising the steps of: receiving, in each of a plurality of input waveguides for carrying input optical signals, an optical signal of a predetermined wavelength; directing, through a free space region, the optical signals received in the plurality of waveguides toward a reflective optical grating comprising a plurality of unequal length waveguides each terminated in a reflective element; and reflecting the optical signals directed to the optical grating toward a single one of a plurality of waveguides for carrying multiplexed optical signals interleaved with the plurality of waveguides for carrying unmultiplexed optical signals.
Claim 9
Independent Claim
99 words
A method of demultiplexing a multiplexed plurality of optical wavelengths, comprising the steps of: receiving, in one of a plurality of input waveguides for carrying input optical signals, a plurality of multiplexed optical signals; directing, through a free space region, the input optical signals toward a reflective optical grating comprising a plurality of unequal length waveguides, each terminated in a reflective element; and reflecting each of the multiplexed optical signals from the grating toward a respective one of a plurality of output waveguides for receiving unmultiplexed optical signals interleaved with the plurality of waveguides for carrying multiplexed opticals signals.
Claim 10
Independent Claim
99 words
A method of demultiplexing a multiplexed plurality of optical wavelengths, comprising the steps of: receiving, in one of a plurality of input waveguides for carrying input optical signals, a plurality of multiplexed optical signals; directing, through a free space region, the input optical signals toward a reflective optical grating comprising a plurality of unequal length waveguides, each terminated in a reflective element; and reflecting each of the multiplexed optical signals from the grating toward a respective one of a plurality of output waveguides for receiving unmultiplexed optical signals interleaved with the plurality of waveguides for carrying multiplexed opticals signals.
Claim 11
Independent Claim
98 words
An apparatus, comprising: a first plurality of waveguides; a second plurality of waveguides coupled to the first plurality of waveguides so that electromagnetic energy flowing in at least one of the first plurality of waveguides illuminates a first end of each of the second plurality of waveguides; and at least one reflective element directly connected to a second end of at least one of the second plurality of waveguides; in which the first plurality of waveguides comprises a first group of input waveguides and a second group of output waveguides interleaved with the first group of input waveguides.
Claim 12
Independent Claim
98 words
An apparatus, comprising: a first plurality of waveguides; a second plurality of waveguides coupled to the first plurality of waveguides so that electromagnetic energy flowing in at least one of the first plurality of waveguides illuminates a first end of each of the second plurality of waveguides; and at least one reflective element directly connected to a second end of at least one of the second plurality of waveguides; in which the first plurality of waveguides comprises a first group of input waveguides and a second group of output waveguides interleaved with the first group of input waveguides.
Claim 13
Independent Claim
104 words
An apparatus, comprising: a first plurality of waveguides; a second plurality of waveguides coupled to the first plurality of waveguides so at electromagnetic energy flowing in at least one of the first plurality of waveguides illuminates a first end of each of the second plurality of waveguides; and a reflective element directly connected to a second end of each of the second plurality of waveguides; in which the reflective elements each comprises a Bragg reflector; and in which each of the second plurality waveguides is curved so that each Bragg reflector is displaced with respect to every other Bragg reflector by only linear displacements.
Claim 14
Independent Claim
104 words
An apparatus, comprising: a first plurality of waveguides; a second plurality of waveguides coupled to the first plurality of waveguides so at electromagnetic energy flowing in at least one of the first plurality of waveguides illuminates a first end of each of the second plurality of waveguides; and a reflective element directly connected to a second end of each of the second plurality of waveguides; in which the reflective elements each comprises a Bragg reflector; and in which each of the second plurality waveguides is curved so that each Bragg reflector is displaced with respect to every other Bragg reflector by only linear displacements.
Claim 15
Dependent Claim
116 words
An communication system, comprising: a means for producing one or more optical signals for carrying information from a transmitter to a receiver; at least one multiplexing/demultiplexing device for receiving the one or more optical signals comprising: a first plurality of waveguides; a second plurality of waveguides coupled to the first plurality of waveguides so that electromagnetic energy flowing in at least one of the first plurality of waveguides illuminates a first end of each of the second plurality of waveguides; and at least one reflective element directly connected to a second end of at least one of the second plurality of waveguides; and a means for transmitting output signals from the multiplexing/demultiplexing device to a receiver.
Claim 16
Dependent Claim
116 words
An communication system, comprising: a means for producing one or more optical signals for carrying information from a transmitter to a receiver; at least one multiplexing/demultiplexing device for receiving the one or more optical signals comprising: a first plurality of waveguides; a second plurality of waveguides coupled to the first plurality of waveguides so that electromagnetic energy flowing in at least one of the first plurality of waveguides illuminates a first end of each of the second plurality of waveguides; and at least one reflective element directly connected to a second end of at least one of the second plurality of waveguides; and a means for transmitting output signals from the multiplexing/demultiplexing device to a receiver.
References Cited (Backward Citations)
US3600594A
Cited
US4746186A
Cited
US4886333A
Cited
EP0250824A1
Cited
US4940306A
Cited
US4904042A
Cited
US4923271A
Cited
US5002350A
Cited
JPH03263003A
Cited
US5136600A
Cited
US5142660A
Cited
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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) | 1998-09-11 | 1999-03-13 | 1999-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-11 | 2003-03-13 | 2003-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-11 | 2007-03-13 | 2007-09-12 | $7700.00 | Window Closed / Lapsed |