Integrated photonics plays a crucial role in scaling up quantum technology.
(AZOtopics) Photonic chips are widely used for quantum computing. These chips are made of materials such as silicon, silicon nitrides, or other semiconductor materials. Quantum computing chips comprise three different functional segments.
The first segment is the input module. Classical laser light is distributed to an array of optical tweezers. Tweezers are microscopic devices that are made of small ring resonators, which, when driven by bright classical light pulses, generate a special quantum state of light called squeezed state.
In the second phase of PIC, the squeezed states enter a network of beam splitters and phase shifters called an interferometer. The interferometer is programmed using software, and user instructions are loaded electronically. The control systems translate these instructions by applying a set of electrical voltages to different components on the chip.
After the quantum states are manipulated and encoded with data, they are ready for read-out. In the third segment of the PIC, each output of the chip is directed to a special single-photon counter. These detectors measure how many photons are present in each output yielding an array of integers that are reported back to the user. The result of the computation or algorithm is encoded in the statistics of this photon number data.
While many advances have been achieved, to extract the full potential of quantum technology, the number of controllable qubits in a quantum system must be scaled up.
Hundreds of times higher qubits than what is possible today will be needed to make impactful quantum devices. However, translating results from the lab environment to everyday applications has been a major challenge.
According to scientists, more research and development is required to overcome some of the current limitations. One experimental approach that can benefit future photonic quantum technology is to develop new classical photonic integration methods in parallel.
Since classical integrated photonic devices can be used for quantum applications, chip-level integration will be a crucial development for scaling up and translating laboratory efforts into commercial technologies.