Despite rapid advancements in lidar technology， extremely long-range observation remains a significant challenge. Recently， 2 μm lasers have demonstrated a potential to be applied in CDWL（Coherent Doppler Wind Lidar） system， for its high atmospheric penetration capability through the atmosphere and high potential laser power. In this study， we present a 2 μm balanced detector that consists of a pair of commercial positive-intrinsic-negative （PIN） diodes with a low-noise transimpedance circuit. To meet the high bandwidth requirements， the highspeed transimpedance circuit and bias voltage tuning method were utilized to overcome the large capacitance of PIN diodes. The circuit transfer function， stability analysis and noise calculation have been studied. The detector was co-packaged with a data acquisition module for convenient data transmission and bias voltage control. The characteristics of the detector， including bandwidth， noise and bias voltage influence， are evaluated in laboratory. Results show that the RMS value of the balanced detector background noise is 539 μV and the bandwidths of the two diodes are 110.8 MHz and 110.3 MHz， respectively. The evaluation results show that the balanced detector meets the wind measurement requirements and allows for a 1.45× increase in bandwidth through bias voltage tuning. Our work offers insights into lidar detector design and bandwidth enhancement， providing a valuable reference for researchers and professionals in the field. More importantly， it lays a critical foundation for future ultra-long-range and space-borne 2 μm coherent wind lidar systems by addressing key device-level challenges.