A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving 50 ft transmission lines and a pair of feedback networks for offset cancellation. At a positive supply voltage of 2 V and a negative supply voltage of - 2V, the power dissipation is about 280 mW. The small-signal gain is higher than 46 dB and the input dynamic range is about 40 dB with a constant single-ended output voltage swing of 400 mV. Satisfactory eye-diagrams are obtained at the bit rate of 12 Gbit/s limited by the test set-up. The chip area is 1.15 mm ×0.7 mm.
The vertical cavity surface emitting laser (VCSEL) arrays and VCSEL-based optical transmission modules are investigated.It includes the VCSEL's spectral characteristic,modulation characteristic,high frequency characteristic,and compatibility with microelectronic circuit.The module consists of 1×16 VCSEL array and 16-channel lasers driver with 0.35μm CMOS circuit by hybrid integration.During the test process,the module operates well at more than 2GHz in -3dB frequency bandwidth.
