Designing of a small-area optical receiver (Rx) may require intuitive solutions, such as building single-ended Rx and utilizing some of the advantages of differential Rx. Optical Rx should provide sufficient gain and frequency operation for feeding to subsequent blocks including clock and data recovery circuit (CDR) and/or Serializer and Deserializer (SerDes) with reduced size for building compact optical Rx modules. Therefore, we have designed single-ended and differential Rx modules and analyzed their performance comparatively in terms noise, power, size, and gain. Optical Rx chips have been fabricated using 0.13μm complementary metal-oxide-semiconductor (CMOS) technology to demonstrate performance of optical Rx modules. The fabricated single-ended Rx chip core size is equal to 0.035mm2 and consumes power of 10.3mW at 1.3V. The fabricated differential Rx chip core size is equal to 0.135 mm 2 and consumes power of 65.8mW at 1.3V. The input-referred noise (IRN) of singled-ended and differential optical Rx chips is equal to 34pA/√Hz and 30pA/√Hz, respectively. The 3-dB bandwidth of differential and single-ended Rx optical modules is equal to 2.5GHz and 3GHz, respectively.