A Direct Digital Synthesizer-Based Arbitrary Waveform Generator for Envelope Modulation in Trapped-Ion Quantum Computer Operating at 4K

This paper presents an Arbitrary Waveform Generator (AWG) based on a Direct Digital Synthesizer (DDS) with a sub-Hz frequency resolution. The proposed circuit generates a low-frequency arbitrary signal used for amplitude modulation of a microwave (MW) carrier signal, required for qubit entanglement operations with an enhanced gate fidelity in a Trapped-Ion Quantum Computer (TIQC). This is realized by utilizing a DDS as a custom waveform generator. The proposed mixed-signal circuit operates at a 2.5 V analog and 1.5 V digital supply and dissipates $52 \mu \mathrm{~W} / \mathrm{MHz}$. The chip was measured from 4 K to 297 K and achieves a SFDR of $\mathbf{4 2} \mathbf{~ d B c}$. The design is fabricated in Infineon’s $\mathbf{0. 1 3} \mu \mathrm{m}$ SiGe BiCMOS technology and has a core area of $0.45 \mathrm{~mm}^{2}$. To the best of the authors’ knowledge, this is the first reported AWG for amplitude envelope modulation in trapped-ion quantum computer application.