Even though Polar Light Technologies focus is at micro-LEDs for AR, the technology itself have properties which makes it interesting for other applications. Optical interconnects are one, quantum cryptography another.

Optical Interconnects

Our modern society is reliant on efficient digital communication. There is an explosive growth in connected devices and data communication. This massive growth requires connections between devices orders of magnitude faster, higher capacity and more power efficient than today. Optical interconnects provide high bandwidth, low power and low latency compared to traditional electrical interconnects.

Current Limitations

Conventional wire solutions will not provide the communication needed in the future, as they are limited by the connection speed between components, not by the intrinsic component speed. This limitation, known as the interconnect bottleneck, is due to the rapid improvements in performance of computer systems: these have chiefly been achieved by downscaling minimum feature sizes of integrated circuits (ICs). The downscaling of the minimum feature size also results in tighter packing of the wires connecting microprocessor elements. As minimum feature sizes decrease, these negative effects become increasingly important, until communication delays between IC elements become comparable to the computation delay of the actual elements. This is becoming a major problem in high-performance electronic systems. The interconnect bottleneck can be solved by utilizing optical interconnects to replace metallic wiring.

Our Technology

Polar Light Technologies has developed a unique nanostructure device, containing arrays of elongated pyramidal quantum dots structures. These nanostructure arrays will provide highly efficient direct generation of polarised light, with the potential for 100-1000x higher spatial density and capacity in optical interconnects (from 0.2 Gb/s to 20-200 Gb/s), supporting the next generation of high-speed communication networks.

Our nanostructure device consists of arrays of elongated pyramidal structures of nitride based InGaN semiconductor materials with a quantum dot at their peak, with unique characteristics:

1) direct emission of single to multiple linear polarised photons

2) an unprecedented high degree of polarisation (~85%), in at least 3 principle directions (0/60/120°)’

3) potential tuneability over a broad spectral range from UV through visible to IR

Potentially the optical interconnects should replace the electrical links in short reach applications, such as data centers, board-to-board, inter-chip, and intra-chip communications.

Quantum Cryptography

Quantum cryptography, if established, is a form of secure communication that is conjectured to be impossible to intercept, in contrast to classical cryptography. In quantum cryptography, single photons are employed to generate and transmit a key; A binary code can be assigned to individual photons. Once the key is generated, coding and encoding using the normal secret-key method can take place.

Current Limitations

Based on the global need of secure communication, there have been significant efforts over the last decades to realize quantum cryptography schemes experimentally. For such a realization of quantum cryptography, there is a need to generate a flow of polarized single photons and the polarization direction, has to be accurately controlled. Further, for an efficient high capacity communication, i.e. a flow of a large number of individual photons per time unit, one needs a high frequency photon generation. Another crucial parameter for efficient and high-capacity communication is a low loss factor for the flow of single photons, i.e. a precise control on the level of individual photons.

Next-generation optoelectronic devices for secure communication in quantum cryptography will accordingly require:

• A high degree of polarization
• A high controllability level of the polarization
• Fast switching rate
• Efficient light extraction
• Small-size dimensions

Our Technology

Polar Light Technologies pyramidal quantum dots generating linearly polarised light, with demonstrated excellent single photon statistics have the potential to fulfill the above given properties.