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CA1229653A Expired / Lapsed CA ⏱️ 0.0 years remaining

Laser differential quantum efficiency control circuit

Assignee: Nortel Networks Ltd
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Filing: 1985-02-11
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Granted: 1987-11-24
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Expires: 2005-02-11
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Abstract

Abstract LASER DIFFERENTIAL QUANTUM EFFICIENCY CONTROL CIRCUIT Abstract of the Disclosure In an injection laser drive arrangement, variations in differential quantum efficiency are compensated by means of a feedback loop which includes a low pass filter and the usual PIN diode on the rear face of the laser diode. A second low pass filter, having characteristics identical to the first, filters the input signal. The outputs of the two low pass filters are compared and integrated to provide a control signal for varying the amplitude of the signal applied to the laser diode. With this arrangement, laser output variations due to patterns of bits in the input signal are cancelled out in the control signal, which consequently compensates the differential quantum efficiency. - i -

Inventors

  • 👤 Hyung B. Kim

Bibliographic Details

Application Number —
Jurisdiction CA
Data Source google_patents
Last Synchronized 2026-11-03 11:50
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/0683; H01S5/06835

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 136 words
An injection laser drive arrangement comprising:-means for deriving from a digital input signal two signals each having a power spectrum that is substantially the same as the power spectrum as said input signal; drive means for supplying to said injection laser a drive signal dependent upon a control signal and one of said two signals; detector means for detecting a light output from said laser; filter means having a bandwidth with a maximum significantly less than that of said output signal for filtering the output of said detector means; second low pass filter means having a transfer function substantially identical to that of the first-mentioned filter means and serving to filter the other of said two signals; and comparator means for comparing respective outputs at the first-mentioned and second filter means to provide said control signal.
Claim 2
Dependent Claim 136 words
An injection laser drive arrangement comprising:-means for deriving from a digital input signal two signals each having a power spectrum that is substantially the same as the power spectrum as said input signal; drive means for supplying to said injection laser a drive signal dependent upon a control signal and one of said two signals; detector means for detecting a light output from said laser; filter means having a bandwidth with a maximum significantly less than that of said output signal for filtering the output of said detector means; second low pass filter means having a transfer function substantially identical to that of the first-mentioned filter means and serving to filter the other of said two signals; and comparator means for comparing respective outputs at the first-mentioned and second filter means to provide said control signal.
Claim 3
Dependent Claim 20 words
An injection laser drive arrangement as defined in claim 1, wherein each said filter means comprises a low pass filter.

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