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EP0310174A1
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EP
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Device for optical heterodyne or homodyne detection of an optical signal beam and receiver provided with such a device
Assignee: Koninklijke Philips NV
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Filing: 1988-09-20
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Granted: —
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Expires: 2008-09-20
Abstract
Abstract A device for optical heterodyne detection is described, using only two adjustable elements influencing the state of polarisation and having a limited control range (51, 52) in order to realize an endless polarization control. In a first embodiment a temporary loss of signal intensity of at most 3 dB is accepted. This signal loss is avoided if a circuit of non-adjustable optical components (81, 82, 83) is incorporated in the heterodyne detection device.
Inventors
- 👤 Cathal John Mahon
- 👤 Giok Djan Khoe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 23:37
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/61; H04B10/614; H04B10/63; H04B10/64
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
A device for optical heterodyne or homodyne detection of an optical signal beam, which device comprises a local oscillator, a beam-combining element for combining radiation from the local oscillator with radiation from the signal beam, at least one opto-electrical converter for converting combined optical radiation into an electric signal, a plurality of adjustable elements influencing the state of polarisation and having a limited control range and a control circuit for adjusting the elements influencing the state of polarisation, said control circuit being adapted for endless control of a state of polarisation, characterized in that the device comprises only two adjustable elements influencing the state of polarisation.
Claim 2
Independent Claim
106 words
A device for optical heterodyne or homodyne detection of an optical signal beam, which device comprises a local oscillator, a beam-combining element for combining radiation from the local oscillator with radiation from the signal beam, at least one opto-electrical converter for converting combined optical radiation into an electric signal, a plurality of adjustable elements influencing the state of polarisation and having a limited control range and a control circuit for adjusting the elements influencing the state of polarisation, said control circuit being adapted for endless control of a state of polarisation, characterized in that the device comprises only two adjustable elements influencing the state of polarisation.
Claim 3
Dependent Claim
88 words
A device as claimed in Claim 1, characterized in that in the radiation path between the elements influencing the state of polarisation and the said beam-combining element, a polarisation-sensitive beam splitter and a further beam-combining element are arranged said polarisation-sensitive beam splitter splitting the radiation path into two branches which are combined again in the further beam-combining element, whereby one of the branches accommodates a state of polarisation converter for converting the state of polarisation of the polarized radiation through this branch into the orthogonal state of polarisation.
Claim 4
Dependent Claim
47 words
A device as claimed in Claim 1 or 2, characterized in that the said beam-combining element has two outputs from which radiation is incident on two opto-electrical converters which convert the radiation into electric signals, and whose outputs are connected to the inputs of a differential amplifier.
Claim 5
Dependent Claim
32 words
A device as claimed in Claim 1, 2 or 3, characterized in that the two adjustable elements influencing the state of polarisation are arranged in the radiation path of the signal beam.
Claim 6
Dependent Claim
27 words
A device as claimed in Claim 1, 2, 3 or 4, characterized in that the two adjustable elements influencing the state of polarisation are linearly birefringent elements.
Claim 7
Dependent Claim
35 words
A device as claimed in Claim 1, 2, 3 or 4, characterized in that at least one of the two adjustable elements influencing the state of polarisation is an element rotating the direction of polarisation.
Claim 8
Dependent Claim
20 words
A receiver suitable for receiving optical signals, provided with a device as claimed in any one of the preceding Claims.
References Cited (Backward Citations)
WO1986007513A1
Cited
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