A.3 Attachment 1 TECH_SPEC_for_frequency_synthesizer.pdf

Multi-Channel Frequency Synthesizer for Superconducting Qubit Research

This document defines the technical specification for a multi-channel frequency synthesizer intended to support ongoing and future superconducting qubit research. The laboratory requires a local oscillator (LO) source capable of generating multiple coherent microwave tones with high frequency stability, low phase noise, and precise synchronization across channels. The system need to provide flexible and synchronized outputs to enable accurate qubit control, readout, and multiplexed operation in advanced experimental setups. An acceptable example of a compliant instrument is the Keysight AP4022A Frequency synthesizer (40 GHz) with flexible reference input, fast switching, improved harmonics, and enhanced low phase noise. This product meets the specifications required and it’s an oN-the shelf product.

The frequency synthesizer shall employ a multi-channel architecture with a minimum of two independent output channels. Each channel must be capable of operating up to 40 GHz and phase-coherent with the others to ensure synchronized operation. The architecture needs to support scalability for future system expansion while reducing overall hardware complexity and maintaining consistent high-performance operation. Each channel will support a wide frequency range from 100 kHz to 40 GHz and provide extremely fine frequency resolution on the order of millihertz (mHz). The synthesizer needs to enable precise frequency synthesis across the entire output range and maintain deterministic phase relationships between channels. Independent programmability of frequency, phase, and amplitude for each channel is required.

The output power for each channel should be adjustable from -10 dBm to +20 dBm, with a typical or maximum output power of +20 dBm at 1 GHz. The system needs to exhibit very low phase noise performance, specifically achieving a phase noise level of -145 dBc/Hz or better at a 20 kHz oNset from a 1 GHz carrier. Additionally, the synthesizer should maintain low spurious emissions, improved harmonic performance, and high spectral purity across the full operating frequency range. Fast frequency switching is a critical requirement, and the synthesizer needs to support switching speeds of 20 microseconds or less over the entire frequency range. This capability is necessary to support dynamic qubit control and fast experimental sequencing. The system should include a high-stability internal reference oscillator and provide the capability to phase-lock to an external programmable reference.

This ensures long-term frequency stability and compatibility with external timing systems.

All channels should remain phase-locked and synchronized under both internal and external reference configurations.

Attachment 1

The synthesizer shall be housed in a standard 19-inch rack-mountable chassis suitable for laboratory integration. It must support programmability for frequency, phase, and amplitude control, and should provide standard communication interfaces such as Ethernet, USB, or GPIB to enable integration with experimental control systems. The system shall utilize a proprietary frequency synthesis architecture that enables exact frequency generation with ultra-fine resolution and ultra-fast switching speeds below 20 microseconds. The design needs to minimize system complexity, reduce the need for additional external hardware, and ensure reliable and repeatable performance.

In summary, the required frequency synthesizer needs to deliver multi-channel, phase-coherent microwave signal generation with high stability, low phase noise, fast switching, and scalable architecture, making it suitable for advanced superconducting qubit research applications. The Keysight AP4022A frequency synthesizer (40 GHz), featuring flexible reference input, fast switching, improved harmonic performance, and enhanced low phase noise, is well aligned with these requirements.

Summary of Key Specifications

Parameter Requirement

Number of Channels: ≥ 2

Frequency Range: 100 kHz – 40 GHz

Frequency Resolution: ≤ 1 mHz

Output Power Range: -10 to +20 dBm

Output Power @ 1 GHz: +20 dBm

Phase Noise (1 GHz, 20 kHz): ≤ -145 dBc/Hz

Switching Speed: ≤ 20 µs

Phase Coherence: Required across channels

Reference Clock: Internal + External Locking

Form Factor: 1U, 19” Rack Mount