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EP0605116A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Depolariser for optical components in optical transmission system

Assignee: AT&T Inc
•
Filing: 1993-12-06
•
Granted: —
•
Expires: 2013-12-06
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Abstract

Abstract Previous efforts to measure polarization dependent loss of optical components have been limited in uncertainty to more than 0.01 dB. This is because the power meter used in a test set contains polarization dependent loss which adversely affects the final readings. It is here disclosed that an unpumped erbium doped fiber (36) can convert a received polarized signal into unpolarized amplified spontaneous emission of a longer wavelength if the fiber is of sufficient length to absorb the received signal. By locating the inventive unpumped erbium doped fiber upstream of the power meter (38) of a test set, the polarized signal to the power meter is converted to an unpolarized signal and, therefore, the polarization dependent loss of the power meter can not influence the measurement obtained. <IMAGE>

Inventors

  • 👤 Bruce Mitchell Nyman
  • 👤 Gregory Michael Wolter

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-06 09:41
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/30; G01M11/33; G01M11/337; G01M11/333; H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2572

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 32 words
A depolarizer comprising an unpumped doped optical fiber (36) of a length sufficient to absorb an applied polarized signal to produce from the applied signal unpolarized amplified spontaneous emission of longer wavelengths.
Claim 2
Dependent Claim 21 words
The depolarizer of claim 1 wherein said doped optical fiber is of a length sufficient to completely absorb the applied signal.
Claim 3
Dependent Claim 13 words
The depolarizer of claim 1 wherein said optical fiber is doped with erbium.
Claim 4
Dependent Claim 13 words
The depolarizer of claim 1 wherein said optical fiber is doped with neodymium.
Claim 5
Dependent Claim 168 words
A test set for measuring polarization dependent loss of an optical component comprising a signal source (22) for generating a polarized signal, an optical isolator (24) coupled to receive the signal from the signal source, an optical tap (30) coupled to divide the optical signal from the optical isolator into a first signal and a second signal, a polarization controller (32) coupled to receive the first signal from the optical tap, an unpumped doped optical fiber (36) coupled to receive the first signal from the polarization controller, the unpumped doped optical fiber having a length sufficient to absorb fully the received first signal and produce from the received first signal unpolarized amplified spontaneous emission of longer wavelength, a power meter (38) coupled to receive the second signal from the optical tap and the unpolarized amplified spontaneous emission from the unpumped doped optical fiber, and means to locate an optical component whose polarization dependent loss is to be measured between the polarization controller and the unpumped doped optical fiber.
Claim 6
Dependent Claim 16 words
The test set of claim 5 wherein said unpumped doped optical fiber is doped with erbium.
Claim 7
Dependent Claim 16 words
The test set of claim 5 wherein said unpumped doped optical fiber is doped with neodymium.
Claim 8
Dependent Claim 13 words
The test set of claim 6 wherein said signal source comprises a laser.
Claim 9
Dependent Claim 16 words
The test set of claim 8 further comprising a modulator (20) coupled to modulate said laser.
Claim 10
Dependent Claim 36 words
The test set of claim 9 further comprising an interference filter (26) interposed between the optical isolator and the optical tap, and a second optical isolator (28) interposed between the interference filter and the optical tap.

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