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What We Do

The interconnect capability of electrical wires between chips or processing cores will not scale to keep up with the ability to compute.”

National Research Council

Optical Interconnects

One of the cornerstones of PhotonIC Corp.’s pioneering technology is its development of novel optical interconnect architectures that promise to supplant copper wiring in carrying data from board to board, from chip to chip, and from one component to another within a single chip.

As data rates within microelectronic systems increase, the bandwidth of traditional copper interconnects is increasingly hampered by heat dissipation, signal distortion, and cross-talk. Optical interconnects offer higher bandwidth, lower latency, and diminished power consumption along with immunity to electromagnetic interference. If optical interconnects are to be a viable and cost-effective alternative to copper, however, they must be fabricated in a way that is compatible with conventional electronic circuitry.

PhotonIC Corp. is answering the need for high-performance optical interconnects by using silicon-on-insulator (SOI) substrates, rather than higher-cost materials such as indium phosphide, to pursue groundbreaking interconnect designs that are at once high speed, low power, and low cost. By this means, we hope to overcome the fundamental limitations of copper interconnections, allowing for exponential increases in data transmission and capacity at lower power and cost.

Photonic Building Blocks

Unlike conventional electronic circuits, in which the dominant device is the transistor, the creation of integrated photonic circuits requires the stringing together of individual “building blocks” of photonic elements in appropriate sequences. This in turn requires extensive knowledge of photonic design, optical power budget analysis, and materials science along with a thorough understanding of compatible fabrication techniques. PhotonIC Corp. possesses capabilities that span all of these areas.

Devices developed by APIC Corporation and transferred to PhotonIC Corp. for commercial application encompass a range of digital and analog network components whose capabilities dramatically exceed those of current copper-based technologies. These include:

  • An integrated digital transmitter that is tunable to any of 32 wavelengths. This fully packaged module consists of (1) a tunable laser/semiconductor optical amplifier/modulator that is fiber-pigtailed for optimal coupling efficiency, and (2) a printed circuit board that controls the transmitter module. The transmitter has a high level of redundancy and supports OC-192 and 10-Gbps Ethernet transmission protocols on standard WDM channels in C-band.
  • An integrated digital receiver designed to receive any four of 32 wavelengths. This component comprises (1) an optical chip that provides wavelength demultiplexing, an array of integrated photodiode detectors, an ASIC chip for signal amplification and switching, and ruggedized packaging; and (2) an electronics board that provides power, control, and data logging. The receiver module accepts signals up to OC-192 and 10-Gbps Ethernet on standard WDM channels and is directly extendable to a range of data networking and telecommunications applications.
  • An analog transmitter that converts a single analog electrical signal to amplitude-modulated light and operates in conjunction with a high-output-power (≥70-mW) laser with low relative-intensity noise, yielding a high signal-to-noise ratio. A laser array can be used to achieve 16 channels 200 GHz apart that can be multiplexed on the same fiber for phase-sensitive applications.
  • An analog receiver that is designed to accept high-input optical RF power and deliver high-linearity outputs. It converts optical to electronic signals by means of a photodetector and an integrated-output RF transmission line. The receiver chip can be integrated with a tunable wavelength filter to allow for single-wavelength/single-channel operation.

Tunable digital transmitter (left) and digital receiver (right).

Analog transmitter (left) and receiver (right).

Germanium (Ge) Laser

Yet another breakthrough that promises to transform the nature and scope of conventional electronics has been the recent development by APIC Corporation—PhotonIC Corp.'s sister entity—of an on-chip germanium laser that can be used as a light source for the next generation of photonic semiconductor chips.

Although optical interconnection technology holds the key to overcoming the inherent performance limitations of copper, the full realization of optical integration pivots on the development of a monolithically integrated, on-chip light source that is compatible with silicon. However, the lll-V materials typically used for semiconductor lasers have proven difficult to integrate into a silicon platform.

APIC Corporation, working in conjunction with MIT and Stanford University, has succeeded in overcoming these limitations by harnessing proprietary straining and doping techniques to create a germanium laser that can be readily integrated with silicon. By this means, we hope to pave the way for a new generation of photonic chips that will allow for vast increases in processor speed and computational capacity at a fraction of current manufacturing costs. Once reduced to practice, this technology will be transferred to PhotonIC Corp. for use across a wide range of computer and networking applications.