Abstract

In the present paper, under thermal-irradiated operating conditions, the performance characteristics of high speed laser diodes (based on Vertical Cavity Surface Emitting Laser (VCSELs)) are deeply and parametrically investigated. The processed characteristics are: the harmonic response transfer function, the resonance frequency, 3-dB bandwidth and the rise time. These diodes affect the transmitted bit-rate in high-speed advanced optical communication systems. The effects of both ambient temperature (and consequently the inner temperature), the injected current (power) and the dose of irradiation are deeply investigated. The pulse rise time and the resonance frequency as well as the 3-dB bandwidth are the major criterions of the device speed. Nonlinear relations are correlated to investigate the power-current and the voltage-current dependences of the devices. Although a considerable amount of radiation effects studies on individual devices exposed to a variety of radiation conditions is reported in literature, only little information is available on the radiation tolerance at high total dose ( > 1 MGy) and under neutron radiation.

Key words: VCSEL, performance characteristics, radiation.