Method for realizing precise target gain control for hybrid fibre amplifier, and hybrid fibre amplifier

A method for realizing precise target gain control of a hybrid fibre amplifier, being characterized in comprising the following steps:

• Step 1:
• controlling an erbium-doped fibre amplifier of the hybrid fibre amplifier firstly to output light with a constant power P1 when the hybrid fibre amplifier starts pumping;
• Step 2:
• after the erbium-doped fibre amplifier outputs the constant power for a period of time t1, controlling a Raman fibre amplifier of the hybrid fibre amplifier to detect a source signal optical power S1 and an out-of-band ASE power Source_ASE1 contained in the source signal light;
• Step 3:
• reading a target gain G1 from a control unit part and a relationship between the gain and the out-of-band ASE obtained by calibration to calculate a target ASE power PG1_ASE1, and calculating a target out-of-band ASE power Target_ASE_1 compensated by the source ASE:
• Target_ASE_1=PG1_ASE1+Source_ASE1*G1;
• Step 4:
• controlling the Raman fibre amplifier to start pumping when it is determined that the source signal optical power S1 detected by the Raman fibre amplifier becomes stable, and reading a detection value of the out-of-band ASE power in real-time;
• Step 5:
• comparing the detection value of the out-of-band ASE power read in Step 4 with the Target_ASE_1, and stopping adjustment of the pumping power when the two values are equal to each other;
• Step 6:
• when the pumping power of the Raman fibre amplifier becomes stable, calculating a source signal optical power S2 after starting pumping, and comparing S1 with S2 to calculate a delta Gain ΔG=S2−S1;
• if the delta Gain meets an accuracy requirement, proceeding to Step 8 directly;
• and if the delta Gain does not meet the accuracy requirement, proceeding to Step 7;
• Step 7:
• compensating the delta Gain to the target gain to obtain G2=G1−ΔG;
• repeating Step 3 to calculate a new target out-of-band ASE power ASE3;
• and repeating Step 4, Step 5 and Step 6 in this order;
• Step 8:
• controlling the erbium-doped fibre amplifier to start pumping according to a preset gain requirement so as to achieve a rated control gain of the hybrid fibre amplifier when the pumping power of the Raman fibre amplifier becomes stable.