Chip-sized optical amplifier can intensify light 100-fold with minimal energy
Light does a lot of work in the modern world, enabling all types of information technology, from TVs to satellites to fiber-optic cables that carry the internet across oceans. Stanford physicists recently found a way to make ...
Similar to sound amplifiers, optical amplifiers take a light signal and intensify it. Current small-sized optical amplifiers need a lot of power to function. The new optical amplifier, detailed in the journal Nature, solves this problem by using a method that essentially recycles the energy used to power it.
"We've demonstrated, for the first time, a truly versatile, low-power optical amplifier, one that can operate across the optical spectrum and is efficient enough that it can be integrated on a chip," said Amir Safavi-Naeini, the study's senior author and associate professor of physics in Stanford's School of Humanities and Sciences. "That means we can now build much more complex optical systems than were possible before."
The Stanford-developed device achieves about 100 times amplification, or increases the intensity of a light signal, while only using a couple hundred milliwatts of power—a fraction of what is typically required for existing optical amplifiers of similar size. That efficiency coupled with its small size means the amplifier could be powered by a battery and used in laptops and smartphones.
Less power and less noise
Just like sound amplifiers, optical amplifiers tend to add unwanted noise when they boost a signal. The researchers demonstrated that this amplifier adds as little noise as possible. It also has a broader bandwidth than current amplifiers, meaning it supports a greater optical spectrum. Together, this indicates it has greater data-carrying capacity with less interference.
Close up of an optical amplifier chip, similar to the one detailed in this study, that is being developed in the lab of Stanford physicist Amir Safavi-Naeini. A red laser light shines from an optical fiber on the left to help with aligning the fiber to the chip. Credit: Jim Gensheimer for Stanford University
Stanford doctoral student Devin Dean (right) prepares to measure an optical amplifier chip in the lab of Amir Safavi-Naeini, (left) associate professor of applied physics. Dean, Safavi-Naeini, and Taewon Park (top) are co-authors of the study describing a new low-power optical amplifier chip that can fit on devices as small as a smartphone. Credit: Jim Gensheimer for Stanford University