In this paper, the limitations of the performance of electroabsorption modulators (EAMs) as optical transceivers in passive picocell systems by using the finite-difference time-domain (FDTD) method are theoretically investigated. EAMs with no bias voltage are modeled by the FDTD method with consideration of the interaction between electromagnetic fields and optical powers in optical waveguides. Transmission and responsivity of EAMs according to various optical input powers and chip lengths are calculated. Then, power margins of the downlink and uplink paths are estimated to define the service ranges of the passive picocell systems. In addition, EAMs with biased voltage are characterized for comparison. The results suggest that the service range of the passive picocell system using a no-biased EAM can be extended up to 20 m with a chip length of 400 μm and an optical input power larger than 10 dBm.
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