Effects of the electrical signals generated in passive sections of SG-DBR lasers

We investigate electrical signals generated in passive sections of a sampled-grating distributed Bragg reflector laser. A DC voltage is applied to one of the passive sections, and a negative current in the circuit is observed with a low voltage biased. Experimental results demonstrate that the negative current is generated due to photovoltaic effect. This effect could be enhanced or suppressed by adjusting the parameters of p-n junctions in the passive sections. On account of this effect, the passive sections can be utilized as inner photodetectors to control the laser power, which greatly simplifies the laser packaging and reduces the cost.