§
Luxuse
Patent Intelligence
Sign In
Patent EP0314097A2 successfully refreshed from Google Patents.
← Back to Patent Explorer
EP0314097A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

An optical heterodyne homodyne detection apparatus

Assignee: NEC Corp
•
Filing: 1988-10-26
•
Granted: —
•
Expires: 2008-10-26
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract In an optical heterodyne homodyne detection apparatus, signal light (1) and local oscillation light (2) are combined, and the combined light (3) is received in an optical detector (4) to produce intermediate frequency signal which is then demodulated (7) thereby producing base band signals. The frequency sweep of the intermediate frequency signal is performed so that the frequency of the intermediate frequency signal becomes a predetermined value. During the frequency sweep, at least one polarization of the signal light and the intermediate frequency signal is scrambled, and is stopped when the frequency becomes the predetermined value. Thereafter, polarizations of the signal light and the local oscillation light are coincided with each other in accordance with the polarization angle control.

Inventors

  • 👤 Shuntaro Yamazaki

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-08 20:47
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/61; H04B10/615; H04B10/6151; H04B10/63; H04B10/64

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 157 words
An optical heterodyne homodyne detection apparatus comprising, means for sweeping frequency of local oscillation light, means for scrambling polarization of at least one light selected from said local oscillation light and signal light supplied from an optical transmitter, means for controlling polarization angle of said at least one light, means for producing intermediate frequency signal by combining said local oscillation light and said signal light, and a controller for controlling the frequency sweep of said local oscillation light, the polarization scrambling of said at least one light, and the polarization angle control of said at least one light, wherein said frequency sweep and said polarization scrambling are performed under the control of said controller, and are stopped when frequency of said intermediate frequency signal becomes a predetermined value whereafter said polarization angle control is performed under the control of said controller to result in the coincidence of polarizations between said local oscillation light and said signal light.
Claim 2
Dependent Claim 157 words
An optical heterodyne homodyne detection apparatus comprising, means for sweeping frequency of local oscillation light, means for scrambling polarization of at least one light selected from said local oscillation light and signal light supplied from an optical transmitter, means for controlling polarization angle of said at least one light, means for producing intermediate frequency signal by combining said local oscillation light and said signal light, and a controller for controlling the frequency sweep of said local oscillation light, the polarization scrambling of said at least one light, and the polarization angle control of said at least one light, wherein said frequency sweep and said polarization scrambling are performed under the control of said controller, and are stopped when frequency of said intermediate frequency signal becomes a predetermined value whereafter said polarization angle control is performed under the control of said controller to result in the coincidence of polarizations between said local oscillation light and said signal light.
Claim 3
Dependent Claim 106 words
An optical heterodyne homodyne detection apparatus according to claim 1 further comprising, an envelope detection circuit for detecting the presence and non-presence of said intermediate frequency signal, a channel discrimination circuit for discriminating channels, and a frequency discriminator for detecting the frequency fluctuation of said intermediate frequency signal, wherein said frequency sweep and said polarization scrambling are controlled in accordance with signals supplied from said envelope detection circuit and said channel discrimination circuit to said controller, and said frequency of said intermediate frequency signal is stabilized in accordance with signal supplied from said frequency discriminator to a local oscillation light source for said local oscillation light.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Maintenance schedule is calculated for granted US utility patents.

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag