Optical power control circuit

Abstract

The invention discloses an optical power control circuit which comprises an APC (Automatic Power Control) loop and a microcontroller, wherein the APC loop comprises a semiconductor laser and an integral amplifier; the semiconductor laser is connected with a current induction circuit; and the microcontroller is used for monitoring the bias current through the current induction circuit and is used for adjusting the target power of the APC loop. The optical power control circuit has the beneficial effect that through monitoring the bias current and comparing with additional two threshold currents, when an MCU (Microprogrammed Control Unit) is used for adjusting the target power, the situations of overload and sudden shutdown of the laser are prevented, the damage of the semiconductor laser caused by overload and forced shutdown is avoided, and the sudden failure of a data chain using the laser caused by overload and sudden shutdown is also avoided.

Description

technical field [0001] The invention relates to the field of optical fiber communication, in particular to an optical power control circuit. Background technique [0002] Semiconductor lasers (LDs) have the advantages of good monochromaticity, good directivity, small size, and high utilization of optical power. However, the optical power output of semiconductor lasers is greatly affected by changes in the external environment. figure 1 It shows the relationship between the output power and the forward drive current of a typical semiconductor laser at different temperatures (for clarity, figure 1 The approximate straight part of the middle bottom is raised on purpose). Depend on figure 1 It can be seen that when the driving current is lower than the threshold current I th , the laser can only emit fluorescence, and the output optical power is approximately zero; only when the driving current is greater than the threshold current of the laser, the laser can work normally an...

AI Technical Summary

Problems solved by technology

[0004] However, when the temperature rises, due to the threshold current I th increases, the slope efficiency S decreases, and to keep the optical power stable, the APC circuit will increase the DC bias current I BIAS , which may turn off the laser, which may cause hardware damage in real-time systems

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