Intel Claims First Single-chip Silicon Laser Based On SOI

SAN JOSE, Calif. — In what could disrupt the photonics space, Intel Corp. on Wednesday (Feb. 16) described what it claims is the world's first silicon-based continuous-wave laser on a single chip — build around silicon-on-insulator (SOI) and other technologies.

In the lab, Intel (Santa Clara, Calif.) said it has developed a test chip, which consists of a silicon laser cavity on a single device. Making use of a technology called the Raman Effect, the test chip itself consists of eight lasers on a device that measures 16- x 16-mm.

The technology is still in the R&D stage, but Intel is looking to drive down the costs of photonics, by bringing low-cost CMOS silicon into the arena. In general, the critical components within an optical system are based on expensive and exotic technologies, such as gallium arsenide (GaAs), indium phosphide (InP), lithium niobate, among others.

Intel's technology is part of an effort to devise silicon-based building blocks for the photonics space. The single-chip laser technology brings the industry one step closer to the long-awaited, monolithic photonic chip, according to the company.

"Intel has a long-term vision of siliconizing photonics," said Victor Krutul, senior manager of silicon photonics strategy at the microprocessor giant.

Products like the silicon-based laser could be rolled out in the commercial market by the end of this decade, said Mario Paniccia, director of the Photonics Technology Lab at Intel. Applications include communication systems, medical equipment and others, he said.

The company is expected to report the results of the technology in today's Nature. In its research, Intel claims to have demonstrated a continuous-wave silicon Raman laser — or what it calls a "Raman" amplifier. In addition, the company is said to have overcome the "two-photon absorption" problem to produce the device.

"We have demonstrated stable single mode laser output with side-mode suppression of over 55dB and linewidth of less than 80-MHz," according to Intel's description of the technology in Nature.

The company claims to have made another breakthrough in the arena. "Because of the nonlinear optical loss associated with two-photon absorption (TPA)-induced free carrier absorption (FCA), until now lasing has been limited to pulse operation," according to Intel. "Specifically, we show that TPA-induced FCA in silicon can be significantly reduced by introducing a reversed-biased p-i-n diode embedded in a silicon waveguide."

The laser is built around a low loss SOI rib waveguide, whose facets are coated with multilayer dielectric films. "The silicon rib waveguide is fabricated on the surface of an undoped SOI substrate using standard photolithographic patterning and reactive ion etching techniques," according to Intel's description in Nature. "The p-i-n structure was formed by implanting boron and phosphorous in the slab on either side of the rib waveguide."