Laser diode monitoring via current mirroring
AssigneeInternational Business Machines Corporation
InventorsStephen John Ames, Michael William Marlowe, Christopher K. White
Life of this patent
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Abstract
An apparatus, program product and method enable a host system to read a signal or signals that are proportional to the output power and/or the bias of a laser in a fiber optic link connected to that host system without breaking that link. By reading one or more of these signals and being aware of the laser characteristics, the “health” of the laser is known and the integrity of the link is maintained. Consequently, the host system has a predictive tool which is able identify substandard lasers and replace them before a serious, and potentially costly, data disruption occurs.
Claims38
A circuit arrangement comprising:
- (A) a current mirror that current mirrors a first variable signal used in the control of the optical output power of a laser;
- and,
- (B) an output circuit, coupled to the current mirror wherein the output circuit outputs a second signal that varies in proportion to the optical output power of the laser to provide an indication of the optical output power of the laser.
A method of monitoring the optical output power of a laser, the method comprising:
- (A) mirroring a current of a first variable signal that is used to control the optical output power of a laser to generate a mirrored signal that varies in proportion to the optical output power of the laser;
- and,
- (B) outputting the mirrored signal as an indication of the optical output power of the laser.
A fiber optic transceiver, comprising:
- (A) a laser;
- (B) a monitor circuit that current mirrors a first variable signal used to control the optical output power of the laser and outputs a current mirrored signal that is proportional to the optical output power of the laser to provide an indication of the optical output power of the laser.
An apparatus, comprising:
- (A) a processor-less fiber optic transceiver, including:
- (i) a laser;
- (ii) a controller circuit configured to control the optical output power of the laser;
- (iii) a monitor diode configured to receive light emitted by the laser and generate therefrom a feedback signal to the controller circuit;
- and
- (iv) a monitor circuit that current mirrors the feedback signal and outputs therefrom a monitor signal that is proportional to the optical output power of the laser;
- and
- (B) a host coupled to the processor-less fiber optic transceiver, the host configured to receive the monitor signal and calculate therefrom the optical output power of the laser, the host further configured to signal an error in response to detecting the optical output power of the laser being outside an acceptable range.
A circuit arrangement comprising:
- (A) a current mirror that current mirrors a first variable signal used to bias a laser;
- and,
- (B) an output circuit, coupled to the current mirror, wherein the output circuit outputs a second signal that varies in proportion to the bias of the laser to provide an indication of the optical output power of the laser.
Dependencies are inferred from the claim text.