Voltage-Controlled Phase Shifter in a Surface Mount Package for 40- and 100-Gb/s Optical Transceivers

This paper presents an 18-to-32 GHz voltage-controlled phase shifter in a compact surface mount package for both 40- and 100-Gb/s optical transceivers. The InP HBT phase shifter chip includes a wideband vector modulator and a pseudo-sine-cosine generator that enables 810° phase control with only one control voltage. A quadrature splitter using a polyphase filter with Cherry-Hooper amplifiers enables wideband vector modulation at up to 32 GHz. A bandwidth boost technique at an output stage increases the operation frequency and reduces the output-amplitude variation. The phase shifter IC is implemented in a new developed compact 5.5 × 5.5 × 2.2 mm³ surface mount package with over 32-GHz bandwidth. A new evaluation board exhibits phase shift operation with linear phase control for 18-to-32 GHz signal. Small phase shifts are observed for environment changes of power voltage and temperature variations. To our knowledge, this is the first voltage-controlled phase shifter with a phase control range exceeding 4π (720°) above 30 GHz.