Method of mode detection and control in semiconductor lasers
AssigneeMotorola, Inc.
InventorsPaul Claisse, Philip Kiely
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Abstract
A method of controlling the spatial mode of the output of a semiconductor laser including the steps of monitoring above threshold spontaneous emissions of a semiconductor laser. Identifying a point at which the rate-of-change, or the slope, of spontaneous emissions versus drive current abruptly changes. Employing feedback to maintain spatial mode control.
Claims9
A method of determining a shift in the spatial mode in which a semiconductor laser is operating comprising the steps of:
- monitoring spontaneous emissions versus drive current of a semiconductor laser;
- and
- identifying a point above a threshold current at which the rate-of-change of the spontaneous emissions versus drive current abruptly changes.
A method of controlling the spatial mode of the output of semiconductor laser comprising the steps of:
- monitoring a rate-of-change of above threshold spontaneous emissions of a semiconductor laser as a function of drive current;
- identifying a point at which the rate-of-change of the spontaneous emissions versus drive current abruptly changes;
- and
- employing feedback to maintain spatial mode control.
A method of controlling the spatial mode of the output of a vertical cavity surface emitting laser comprising the steps of:
- providing a vertical cavity surface emitting laser;
- positioning a lateral detector adjacent the vertical cavity surface emitting laser for receiving laterally emitted spontaneous emissions from the vertical cavity surface emitting laser at an above threshold current;
- monitoring the above threshold spontaneous emissions of the vertical cavity surface emitting laser versus drive current of the vertical cavity surface;
- identifying a point at which a rate-of-change of the spontaneous emissions versus drive current abruptly changes;
- and
- employing feedback to maintain spatial mode control.
Dependencies are inferred from the claim text.