Patent EP0322893A2 successfully refreshed from Google Patents.
EP0322893A2
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EP
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A polarization diversity optical receiving apparatus
Assignee: NEC Corp
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Filing: 1988-12-28
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Granted: —
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Expires: 2008-12-28
Abstract
Abstract In a polarization diversity optical receiving apparatus, signal light (16) is first divided in a polarization separating portion (7) into two signal lights (3) (4) having polarizations orthogonal to each other. Then, the two signal lights are combined with local oscillation lights (5, 6) having polarizations which are coincided with that of a corresponding one of the two signal lights. This results in the reduction of the number of polarization separating portions.
Inventors
- 👤 Makoto Shibutani
- 👤 Shuntaro Yamazaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 20:52
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/61; H04B10/614; H04B10/64
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
126 words
A polarization diversity optical receiving apparatus comprising, a polarization separating means for dividing signal light into first and second signal lights having polarizations orthogonal to each other, an optical dividing means for dividing local oscillation light into first and second local oscillation lights, polarizations of said first and second local oscillation lights coinciding with those of said first and second signal lights correspondingly, a first balanced receiver for receiving said first signal light and said first local oscillation light to produce first intermediate frequency signal, a second balanced receiver for receiving said second signal light and said second local oscillation light to produce second intermediate frequency signal, and a combining and demodulating circuit for receiving said first and second intermediate frequency signals to produce baseband signal.
Claim 2
Dependent Claim
126 words
A polarization diversity optical receiving apparatus comprising, a polarization separating means for dividing signal light into first and second signal lights having polarizations orthogonal to each other, an optical dividing means for dividing local oscillation light into first and second local oscillation lights, polarizations of said first and second local oscillation lights coinciding with those of said first and second signal lights correspondingly, a first balanced receiver for receiving said first signal light and said first local oscillation light to produce first intermediate frequency signal, a second balanced receiver for receiving said second signal light and said second local oscillation light to produce second intermediate frequency signal, and a combining and demodulating circuit for receiving said first and second intermediate frequency signals to produce baseband signal.
Claim 3
Dependent Claim
76 words
A polarization diversity optical receiving apparatus according to claim 1, wherein said first and second balanced receivers each include an optical directional coupler for receiving a corresponding one of said first and second signal lights and a corresponding one of said first and second local oscillation lights to produce two output lights, and a differentially combining circuit for receiving said two output lights to produce a corresponding one of said first and second intermediate frequency signals.
Claim 4
Dependent Claim
33 words
A polarization diversity optical receiving apparatus according to claim 1 or 2, wherein said polarization separating means includes one selected from a polarizing beam splitter and an optical fiber type polarizing beam splitter.
Claim 5
Dependent Claim
40 words
A polarization diversity optical receiving apparatus according to claims 1 to 3, wherein said optical dividing means includes an optical divider having an input and two outputs, and two polarization rotators coupled to said two outputs of said optical divider.
Claim 6
Dependent Claim
60 words
A polarization diversity optical receiving apparatus according to claim 1, wherein said optical dividing means includes an optical coupler having an input and two outputs, and two optical fibers coupled to said two outputs of said optical coupler, polarizations of said two optical fibers being relatively adjusted to those of two optical fibers for said first and second signal lights.
Claim 7
Dependent Claim
51 words
A polarization diversity optical receiving apparatus according to claim 2, wherein said differentially combining circuit includes two photodetectors for converting said two output lights to two electric signals, and a circuit for differentially combining said two electric signals to produce a corresponding one of said first and second intermediate frequency signals.
References Cited (Backward Citations)
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