EP0329186A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Polarization diversity optical receiver for coherent optical communication
Assignee: Fujitsu Ltd
•
Filing: 1989-02-17
•
Granted: —
•
Expires: 2009-02-17
Abstract
Abstract Disclosed is a polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for mixing signal light and the local oscillating light to obtain two polarized components; a detecting circuit (9) for detecting the polarized components to output intermediate frequency signals (e S and e P ); and a frequency control circuit (11) for controlling, in accordance with the intermediate frequency signals (e S and e P ), the oscillating frequency of the optical local oscillating circuit (7). To ensure that the intermediate frequency is not disappeared, the frequency control circuit (11) outputs a combined signal of a sum and a difference of said intermediate frequency signals (e S and e P ).
Inventors
- 👤 Takao Naito
- 👤 Terumi Chikama
- 👤 Shigeki Watanabe
- 👤 Tetsuya Kiyonaga
- 👤 Yoshihito Onoda
- 👤 Hideo Kuwahara
- 👤 Hiroshi Onaka
- 👤 Hideyuki Miyata
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:37
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/61; H04B10/614; H04B10/64
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
157 words
A polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for receiving signal light transmitted through an optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), to obtain two polarized components; a detecting circuit (9) for detecting the signals of the respective polarized components from said mixing circuit (8) to output intermediate frequency signals (e S and e P ); and a frequency control circuit (11) for controlling, in accordance with the intermediate frequency signals (e S and e P ) of the respective polarized components from said detecting circuit (9), the oscillating frequency of said optical local oscillating circuit (7); said frequency control circuit (11) comprising means for obtaining an output signal which is a combined signal of a sum and a difference of said intermediate frequency signals (e S and e P ).
Claim 2
Dependent Claim
157 words
A polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for receiving signal light transmitted through an optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), to obtain two polarized components; a detecting circuit (9) for detecting the signals of the respective polarized components from said mixing circuit (8) to output intermediate frequency signals (e S and e P ); and a frequency control circuit (11) for controlling, in accordance with the intermediate frequency signals (e S and e P ) of the respective polarized components from said detecting circuit (9), the oscillating frequency of said optical local oscillating circuit (7); said frequency control circuit (11) comprising means for obtaining an output signal which is a combined signal of a sum and a difference of said intermediate frequency signals (e S and e P ).
Claim 3
Dependent Claim
64 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 1, wherein said frequency control circuit (11) has delay means for delaying either one of said intermediate frequency signals (e S and e P ), a sum and a difference of the delayed signal delayed by said delay means and the other signal in the two intermediate frequency signals being obtained.
Claim 4
Dependent Claim
104 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 1, wherein said frequency control circuit (11) comprises a subtracter (112) for taking a difference between said intermediate frequency signals (e S and e P ), a first frequency discriminating circuit (113) for effecting frequency discrimination with respect to the output from said first adder (111), a second frequency discriminating circuit (114) for effecting frequency discrimination with respect to the output from said subtracter (112), and a second adder (115) for adding the output from said first frequency discriminating circuit (113) and the output from said second frequency discriminating circuit (114).
Claim 5
Dependent Claim
59 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 1, wherein said frequency control circuit (11) comprises a delay circuit (121) for delaying, before inputting into said first adder (111) and said subtracter (112), either of the polarized components of the intermediate frequency signals (e S and e P ) from said detecting circuit (9).
Claim 6
Dependent Claim
25 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 1, wherein said delay circuit (121) is one providing a one-bit delay.
Claim 7
Dependent Claim
43 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 3, wherein said frequency control circuit (11) has automatic gain control circuits (118 and 119) for respectively adjusting the output gains of said first adder (111) and said subtracter (112).
Claim 8
Dependent Claim
51 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 3, wherein said frequency control circuit (11) comprises power dividers (116 and 117) for inputting the respective polarized components of the intermediate frequency signals from said detecting circuit (9) into said first adder (111) and said subtracter (112).
Claim 9
Dependent Claim
38 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 3, wherein said frequency control circuit (11) comprises doublers for doubling the frequencies of the signals before inputting into said adder circuit and said subtracter.
Claim 10
Dependent Claim
60 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 8, wherein said frequency control circuit (11) comprises a delay circuit (121) for delaying either of said respective polarized components of the intermediate frequency signals (e S and e P ) from said detecting circuit (9) before inputting into said first adder (111) and said subtracter (112).
Claim 11
Dependent Claim
158 words
A polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for receiving signal light transmitted through an optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), and for obtaining two polarized components; a detecting circuit (9) for detecting the signals of the respective polarized components from said mixing circuit (8) to output intermediate frequency signals (e S and e P ); an adding circuit (11A) for adding the respective polarized components of the intermediate frequency signals (e S and e P ) from said detecting circuit (9); a control circuit (11B) for controlling said optical local oscillating circuit (7) depending on the added output of said adding circuit (11A); and local oscillating optical phase modulating means for modulating either one of the polarized components of the local oscillating light from said optical local oscillating circuit (7).
Claim 12
Dependent Claim
158 words
A polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for receiving signal light transmitted through an optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), and for obtaining two polarized components; a detecting circuit (9) for detecting the signals of the respective polarized components from said mixing circuit (8) to output intermediate frequency signals (e S and e P ); an adding circuit (11A) for adding the respective polarized components of the intermediate frequency signals (e S and e P ) from said detecting circuit (9); a control circuit (11B) for controlling said optical local oscillating circuit (7) depending on the added output of said adding circuit (11A); and local oscillating optical phase modulating means for modulating either one of the polarized components of the local oscillating light from said optical local oscillating circuit (7).
Claim 13
Dependent Claim
59 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 1 or 10, wherein said mixing circuit (8) splits the signal light transmitted through said optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7) into two types of polarized components, respectively, and then, mixes the same polarized components to output.
Claim 14
Dependent Claim
67 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 11, further comprising wave dividing means (19) for dividing said local oscillating light from said optical local oscillating circuit (7) into two types of polarized components, said local oscillating optical phase modulating means (13) modulating the phase of either of the polarized components of said local oscillating light from said wave dividing means (19).
Claim 15
Dependent Claim
85 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 11, further comprising wave dividing means (19) for dividing said local oscillating light from said optical local oscillating circuit (7) into two types of polarized components, and said local oscillating optical phase modulating means (13) being one for shifting the frequency of one of the polarized components of said local oscillating light from said wave dividing means (19) by a desired amount with respect to the frequency of the other polarized component.
Claim 16
Dependent Claim
59 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 10, wherein said optical local oscillating circuit (7) comprises two semiconductor lasers (71 and 72) for outputting local oscillating lights of different polarized wave components, the output phase or the output frequency of either of the outputs of said semiconductor lasers (71 and 72) being modulated.
Claim 17
Dependent Claim
41 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 14, wherein the difference between the output frequencies of said two semiconductor lasers (71 and 72) being locked to a desired value through the frequency control circuit (34).
Claim 18
Dependent Claim
163 words
A polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for receiving signal light transmitted through an optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), and for obtaining two polarized wave components; a detecting circuit (9) for detecting the signals of the respective polarized wave components from said mixing circuit (8) to output intermediate frequency signals (e S and e P ); an adding circuit (11A) for adding the respective polarized components of the intermediate frequency signals (e S and e P ) from said detecting circuit (9); a control circuit (11B) for controlling said optical local oscillating circuit (7) depending on the added output of said adding circuit (11A); and detecting output signal modulating means (14) for modulating either of the detected outputs (e S and e P ) of the respective polarized components from said detecting circuit (9).
Claim 19
Dependent Claim
163 words
A polarized wave diversity optical receiver for coherent optical communication comprising: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for receiving signal light transmitted through an optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), and for obtaining two polarized wave components; a detecting circuit (9) for detecting the signals of the respective polarized wave components from said mixing circuit (8) to output intermediate frequency signals (e S and e P ); an adding circuit (11A) for adding the respective polarized components of the intermediate frequency signals (e S and e P ) from said detecting circuit (9); a control circuit (11B) for controlling said optical local oscillating circuit (7) depending on the added output of said adding circuit (11A); and detecting output signal modulating means (14) for modulating either of the detected outputs (e S and e P ) of the respective polarized components from said detecting circuit (9).
Claim 20
Dependent Claim
57 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 16, wherein said mixing circuit (8) splits the signal light transmitted through said optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7) into two types of polarized components, respectively, and then, mixes the same polarized components to output.
Claim 21
Dependent Claim
58 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 1, 10 or 16, wherein said mixing circuit (8) mixes the signal light transmitted through said optical fiber (5) and said local oscillating light from said optical local oscillating circuit (7), and then, splits the mixed signal into two types of polarized components to output.
Claim 22
Dependent Claim
47 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 16, wherein said detected output signal modulating means (14) is the one for modulating the phase of either of the detected output signals (e S and e P ) of the respective polarized components.
Claim 23
Dependent Claim
48 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 16, wherein said detected output signal modulating means (14) is the one for substantially shifting the phase of either of the detected output signals (e S and e P ) of the respective polarized components.
Claim 24
Dependent Claim
35 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 16, wherein said detected output signal modulating means (14) is the one for modulating the frequency of either of the polarized components.
Claim 25
Dependent Claim
81 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 10 or 16, wherein when the power of said signal light is assumed to be 1, the power distribution of the polarized components is expressed in such a way that the power of one of the polarized components is a and the other is (1-a), and the power distribution of the two types of polarized wave components of said local oscillating light are the same (each being 1/2).
Claim 26
Dependent Claim
35 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 12 or 19, wherein the phase modulating by means of said phase modulating means (13) is carried out by changing in time.
Claim 27
Dependent Claim
30 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 3, 11, 14 or 19, wherein said signal light is FSK modulated signal or ASK modulated signal.
Claim 28
Dependent Claim
35 words
A polarized wave diversity optical receiver for coherent optical communication according to claim 17, further comprising doublers for doubling the frequencies of the signals before inputting into said adding circuit to cancel the phase information.
Claim 29
Dependent Claim
40 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 12, 13, 14, 17 or 18, further comprising doublers for doubling the frequencies of the signals before inputting into said adding circuit to cancel the phase information.
Claim 30
Dependent Claim
28 words
A polarized wave diversity optical receiver for coherent optical communication according to claims 8 or 25, wherein said signal light is PSK modulated signal or DPSK modulated signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.