The HL9547 from Hyperlabs is a Bias Tee that operates from 50 kHz to 67 GHz. It can handle an input voltage of up to 30 V and a maximum current of 400 mA. The bias tee has an insertion loss of less than 1.8 dB, amplitude matching of ±0.1 dB, and phase matching of ±4°. It has 1.4-ohms of DC resistance and 110 ps of group delay. This 50-ohm bias tee is available in a module that measures 49.53 x 33.02 x 13.46 mm with 1.85 mm connectors. It is ideal for biasing amplifiers, lasers, optical modulators, optical communication systems, high-speed data systems, level shifting, cascading, and interfacing between devices with incompatible DC operating points applications.