Multi-channel optical receivers clocked at a frequency slower than the data-rate in which different phases are used for each channel are widely used in high data-rate applications. Here, we demonstrate a two-channel optical receiver where both channels share the same clock operating at half of the data-rate frequency. However, instead of using different phases for each channel, the optical input is split and the input to the 2 nd channel is optically delayed with respect to the 1 st channel. Moreover, to improve performance, the duty cycle of the clock can easily become a design parameter. Each channel consists of only one high-bandwidth gain-improved transimpedance amplifier with a pseudo-differential-output and a comparator with offset-nulling. The receiver is fabricated in 65 nm CMOS. To demonstrate the concept, the fabricated die and two photo-detectors are bonded inside a QFN80 package. Measurement results of the receiver show that each channel can sample the input at 8.5 Gbps, resulting in a 17 Gbps total data rate, with a total energy efficiency of 156 fJ/bit, and an input optical modulation amplitude (OMA) sensitivity of -7 dBm without any equalization.

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