Dual laser-power-level control and calibration system for burst-mode and continuous-mode transmitter
AssigneeMaxim Integrated Products, Inc.
InventorsJames Cong Nguyen, Matthew Christopher La Voie, Jan Filip
Life of this patent
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Abstract
Dual laser-power-level control and calibration system for burst-mode and continuous-mode transmitter. A first signal path receives a transmit signal that also drives the transmit laser, and a second signal path receives the output of a monitor diode. The first and second signal paths include filtering so that the two signal paths have a similar frequency response. The upper and lower excursions in both signal paths are compared, and the power levels of the optical transmitter are adjusted based on those comparisons. Embodiments with one control loop and two control loops are disclosed.
Claims46
A method of controlling the power levels of an optical transmitter comprising:
- providing a first signal path for receiving and filtering a transmit signal also used to control the optical transmitter, the first signal path including a first amplifier providing a first output representing a first logic state responsive to the transmit signal and a first level control signal, and a second output representing a second logic state responsive to the transmit signal and a level control signal;
- providing a second signal path for receiving and filtering a signal from a monitor diode monitoring the emission of the optical transmitter;
- the transmit signal as filtered in the first signal path tracking a frequency response of the monitor diode signal as filtered in the second signal path;
- differentially comparing the outputs of a first differential peak detector, the upper excursions of the transmit signal as filtered in the first signal path and the monitor diode signal as filtered in the second signal path to create a first error signal, and differentially comparing the outputs of a second differential peak detector, the lower excursions of the transmit signal as filtered in the first signal path and the monitor diode signal as filtered in the second signal path to create a second error signal;
- using the first and second error signals to adjust a high optical power level and a low optical power level of the optical transmitter to achieve a target average optical power level and extinction ratio.
Apparatus for controlling the power levels of an optical transmitter comprising:
- a first signal path, including a first amplifier and a filter, for receiving and filtering a transmit signal also used to control the optical transmitter, the first amplifier providing a first output representing a first logic state responsive to the transmit signal and a first level control signal, and a second output representing a second logic state responsive to the transmit signal and a second level control signal;
- a second signal path, including a second amplifier and a filter, for receiving and filtering a signal from a monitor diode monitoring the emission of the optical transmitter;
- the filters in the first and second signal paths providing filtered signals having a similar frequency response;
- first differential peak detectors for providing outputs to first and second comparators for comparing, the upper excursions of the transmit signal as filtered in the first signal path and the monitor diode signal as filtered in the second signal path, and the lower excursions of the transmit signal as filtered in the first signal path and the monitor diode signal as filtered in the second signal path;
- and
- circuitry for adjusting a high optical power level and a low optical power level of the optical transmitter based on the output of the first differential peak detectors to achieve a target average optical power level and extinction ratio.
Dependencies are inferred from the claim text.