Crescendo-S is the best commercially available Josephson travelling wave parametric amplifier (J-TWPA), capable of elevating qubit readout towards the state of the art in quantum computers of all sizes. It features cutting-edge gain and noise performance over a wide readout band to enable highly multiplexed and cost-effective readout. Designed to be flexible, scalable and easy to use, Crescendo-S is the readout amplifier for your application.


Achieving cutting-edge gain and noise performance over a wide 1 GHz readout bandwidth, Crescendo-S enables the multiplexed readout of many qubits at once. This enormous reduction in the required overhead in terms of wiring complexity, up-chain components and cost per qubit compared to traditional narrow-band JPA-based readout solutions facilitates future-proof scalable qubit readout.
20 dB gain across 1GHz readout band (S3 model)
-100 dBm input-referred compression power
70% Quantum Efficiency

Easy to setup and use

When you are building a quantum computer, readout amplification should be the least of your concerns. Therefore, Crescendo-S is designed from the ground up with ease-of-use in mind. The current-pumped design is intrinsically simple to tune-up and requires minimal peripheral electronics. Combined with the device-specific characterisation report and expert support included with every device, it is easy to use for experienced and beginning researchers alike.  
Fully packaged and SMA-connectorised
Simple flux-free tune-up and operation
Clear documentation on installation and optimal use
Pre-characterisation report and expert support included

Compact and Highly Scalable

Scalability of readout solutions is paramount to reaching quantum advantage. Crescendo-S is designed and produced to keep pace with even the most ambitious scaling roadmaps. With a compact factor, high-density packaging and highly-automated production process, Crescendo-S is your path to state-of-the-art readout at scale.
Compact 28 x 25 x 10 mm HEMT-sized form-factor
House and shield up to six TWPAs in the high-density Concerto cryo-holder
High-volume production


Serious power, serious value
16 dB typical
A total powerhouse
18 dB typical
State-of-the-art performance
20 dB typical
4 - 5 GHZ
5 - 6 GHZ
6 - 7 GHZ
7 - 8 GHZ
8 - 9 GHZ
Crescendo-S is a versatile amplifier compatible with a wide range of qubit types and available in 1 GHz readout bands between 4 and 9 GHz. Paired with its optional cryo-holder it is ready to go into your fridge straight out of the box.
Compatible with QuantWare’s and your QPUs
Available in all standard readout bands and three models
Customisable readout band upon request


In superconducting quantum computing, Dispersion-Engineered Josephson Travelling Wave Parametric Amplifiers (J-TWPA) play a pivotal role in reading out qubit states. These states are stored in low-power radio frequency (RF) excitations. During readout, equally weak readout pulses are used which would drown in thermal noise at higher temperatures stages without proper amplification.
To achieve fast and high-fidelity readout of the qubit state, ultra-low-noise amplification is required close to the qubit at cryogenic temperatures. The J-TWPA stands as the state-of-the-art solution for this task.

J-TWPAs comprise a long chain of Josephson elements that facilitate a nonlinear wave mixing process which transfers power from a strong pump tone to the low-power signal. By carefully engineering its dispersion properties, this J-TWPA exponentially amplifies the readout signal along its length while adding close to the fundamental lower limit of added noise that results from Heisenberg uncertainty.

Contrary to Josephson Parametric Amplifiers (JPAs), J-TWPAs are transmissive rather than resonant devices, granting them a broad bandwidth unconstrained by resonator limitations. This enables the high degree of frequency multiplexing within a single readout chain that is paramount to scaling quantum computers towards advantage.


To operate Crescendo-S, you will require a pump source (preferably CW), isolators, and a directional coupler for each TWPA. We recommend using wide-band (4-12 GHz) isolators and couplers for optimal performance. During installation, you will also require ESD-protection gear, a torque-limiting wrench and a 50 Ω load for discharging SMA-cables.
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