New Fields of investigation

Person with Circuit Board

HRL IS EXPANDING ITS DIGITAL AND MIXED-SIGNAL INTEGRATED CIRCUIT EFFORTS to increase system and subsystem impact. While high performance analog- to-digital (ADC) conversion continues to be our core expertise, HRL is aggressively developing analog signal processing techniques to further enhance subsystem performance. We continue to deliver low volume production quantities of wideband sigma-delta modulators, and are preparing to produce a modest volume of Indium Phosphide Heterojunction Bipolar Transistor (InP HBT) based integrated circuits (ICs) for LLC Member applications. "Heterojunction" refers to a semiconductor junction that consists of layers of different materials. This produces excellent high frequency operation and low leakage. In this focus area, HRL is also working on enhancing other capabilities, including fast direct digital synthesis ICs and high-speed optoelectronic ICs.

ANALOG-TO-DIGITAL
CONVERTER PERFORMANCE

In 2006, HRL continued to push the frontier of analog-to-digital converter performance along the famous Walden performance curve that was originally developed at HRL in the 1990s. The underlying technology employed to move beyond established performance limitations is a 0.25-µm-emitter Indium Phosphide Dual Heterojunction Bipolar Transistor (InP DHBT) process. The Defense Advanced Research Projects Agency (DARPA)/Air Force Research Laboratory (AFRL) Technology for Frequency Agile Digitally Synthesized Transmitters (TFAST) Program has supported this technology. Innovative ADC design techniques have been used to establish a path to unprecedented component performance.

Another variation of HRL's advanced InP DHBT technology is based on selectively-implanted buried subcollectors (SIBS), and was developed for broadband amplifier applications. This technology is unique in its implementation of ion implantation techniques to improve III-V semiconductor device performance, meaning semiconductors using elements from groups III and V of the periodic table. The SIBS technology is highly beneficial for high-speed optical transmission systems at frequencies up to 40 Gbps that often require voltage swings up to 10 V. Using this technology, HRL demonstrated a state-of-the-art traveling wave amplifier with a 3 dB bandwidth of 61 GHz, and 29 dB of differential gain.

HIGH-SPEED OPTOELECTRONIC
INTEGRATED CIRCUITS

An emerging development in 2006 was the exploration of high-speed optoelectronic integrated circuit technology, based on HRL's core InP HBT, with a goal of 100 Gbps operation. We designed, fabricated, and tested a unitraveling carrier photodiode (UTC), demonstrating operation to a bandwidth of 55 GHz.

developing technologies