Scientists at the National Institute of Standards and Technology have developed a new way to package photonic integrated circuits so they can withstand extreme temperatures and other difficult conditions. The advance could allow photonic chip-based technologies to operate in deep-space probes, inside nuclear reactors, in ultrahigh vacuum systems, at near-absolute zero temperatures and in extremely hot industrial settings.

Demand for advanced semiconductors is rising, prompting the construction of new chip factories and partnerships. Because of increased chip demand, many manufacturers would like use photonic chips in more applications.

However, packaging remains a key obstacle. In chip manufacturing, “packaging” refers to the protective housing and connection system that surrounds a chip and links it to the outside world, including optical fibers, electrical contacts and other components. Good packaging allows the chips to be used in compact, reliable devices without damage or misalignment, NIST said in a news release.

The primary advantage of photonic integrated chips is that they transmit data at high speeds while consuming far less power than conventional chips. Photonic integrated chips currently play a central role in telecommunications, medical diagnostics and advanced sensing.

However, they have had only limited use in more demanding environments because traditional packaging cannot maintain optical connections in the presence of intense radiation, extremely high or low temperatures, or ultrahigh vacuums. Such conditions exist in many places photonic integrated chips could be useful, including quantum computing platforms, space missions, nuclear reactor cores, particle accelerators and industrial and energy applications.

To allow photonic integrated chips to work in these environments, the NIST researchers needed a new way to reliably attach an optical fiber to a photonic chip. NIST said that standard adhesives like organic polymer glues tend to crack, outgas or degrade when exposed to extreme cold, intense radiation, vacuums or heat. When that happens, the chip can no longer operate.

To solve this problem, NIST scientists adapted a technique called hydroxide catalysis bonding, which NIST said “creates an inorganic, glass-like chemical bond between the optical fiber and the photonic chip.” Instead of relying on glue, the process uses a tiny amount of sodium hydroxide solution to fuse the surfaces at the molecular level, forming a rigid, stable connection.

“Our study marks a major step toward bringing the speed and efficiency of photonics into environments where conventional semiconductor chips powered by electric current and photonics chips packaged using traditional methods have not been able to operate,” Klimov said in the news release.

He added that widespread use in mainstream manufacturing will depend on lowering the price and speeding up production. This could be accomplished in several ways, including reducing the curing time, which currently takes about a week but could be shortened to hours or less; scaling up production; and demonstrating long-term reliability across many devices.

”With these steps, broader commercial adoption could follow in the three to five year timeframe or sooner, depending on how much effort is put into further development of this technology,” he said.

By: DocMemory
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