Design of bandwidth controllable 1.25Gb/s optical transmitter and receiver circuits using Si-CMOS process

Abstract

In this paper , we simulated and fabricated 1.25Gbps multichannel optical transmitter and receiver integrated circuit using CMOS process. Transmitter IC consists of buffer, differential amplifier, threshold current level control, and modulation current control parts. Generally, each vertical cavity surface emitting lasers (VCSEL) have different threshold current levels and modulation current characteristics. Therefore, this circuit adopts threshold current control circuit and modulation current control circuit. Not only simulation but also measurement, we obtained bit error rate (BR) characteristics less than $10^{-12} $ at 1.25 Gbps operation. For performing 2R function (Re-amplifying, Re-shaping),Receiver IC consists of preamplifier and limiting amplifier. Preamplifier stage reduces noise signal and amplifies data signal from weak PIN photodetector device. Limiting amplifier generates pulse shape data signal from sine shape signal delivered from preamplifier. we obtained bit error characteristics less than $10^{-12}$ at 1.23Gbps operation.