Effect of series and parallel resistance on low-frequency noise level in semiconductor lasers

By placing the semiconductor lasers in series or parallel with different resistances, the effects of series and parallel resistances on noise level of devices are studied. The effects of serial and parallel resistances on device quality and the correlations between the noise level and reliability of semiconductor lasers are also discussed. The results indicate that the noise level does not change obviously when the devices are placed with serial resistance. At the bias current of 5mA, the parallel resistance also has no obviously effect on noise level. But, when the bias current is 20 mu A, the parallel resistance makes noise level of devices decrease evidently. The devices with lower noise may also be unreliabile.