Electrical noise of laser diodes measured over a wide range of bias currents

Abstract

The electrical noise of commercially available laser diodes, an index guided AlGaInP diode lasing at 635 nm (SDL3038-11) and an InGaAlP-multiquantum well diode lasing at 670 nm (SVL71B), has been investigated over a wide current range of six orders of magnitude. After increasing proportionally with current at small currents (10 nA to 10 μA), the 1/ f noise tends to saturate with increasing current in the range from 10 to 100 μA. For larger operating currents, the 1/ f noise increases again, and with the current proportional to I 2. Different noise sources were discovered below the lasing threshold current. The electrical noise at lower currents must be measured to assess the degradation of the active region of the laser diode.