Introducing the Photonics Lab at GE Global Research
All, I want to introduce my colleague Sabarni Palit who put together the following blog entry with the help of her colleagues in the Photonics Lab at Global Research. Hua Xia, Susanne Lee, Sudeep Mandal, Bill Challener, Sachin Dekate, and Samhita Dasgupta all contributed to the blog. Thanks everybody!
What do the following have in common?
- A sensor that monitors pressure at the bottom of a geothermal well hot enough to kill standard electronics.
- A device that enables safer and more efficient X-Ray and CT machines.
- A gas sensor that detects and determines hydrogen gas purity in a megawatt power generator.
All of these are technologies that the newly formed Photonics Lab in the Micro and Nanostructures Organization at Niskayuna is working on. The Photonics Lab brings together people with expertise in optoelectronics, fiber optics, thin film optics, fiber optic communications, micro and nanophotonic devices and micro electro mechanical systems (MEMs) to apply them to GE products spanning Sensing, Aviation, Energy, Measurement and Control to Power and Healthcare. The Manager of the Photonics Lab is Dr. Samhita Dasgupta. She was really passionate about forming this lab and as she says,“When I talk to eminent researchers in the field, they comment that “they didn’t know GE works in photonics,” we aim to change that perception through advancement of the state of the art and enabling of new products in the diverse areas of Energy, Aviation and Healthcare.”
Photonics is an attractive option when the use of traditional copper wires and/or electronic circuitry cannot handle either the harsh temperatures, high bandwidth requirements or a noisy electromagnetic environment, or just doesn’t provide a specific functionality. Think bright orange fiber optic cables that you have seen being laid down underground or under the sea, that enable long distance telecommunications or the laser for reading data off the DVD in your laptop. But this is only a part of what Photonics can do and what the Photonics Lab does.
We are making solar cells convert sunlight more efficiently to electricity by studying materials, devices and manufacturing processes, and also developing new techniques to enable these studies.
We are reimagining x-ray optics and even studying the feasibility of x-ray lasers. Current medical and inspection x-ray machines use x-ray sources that are little different from the one Coolidge developed in the early 1900s. However, with our new x-ray photonic lenses (invented at GE), micro-structured thin films, and micro-channel cooling, we are reimagining the Coolidge design into a new type of source that enables faster scanning and lower x-ray dose to patients, doctors, and the technicians who operate the x-ray machines.
We are developing next-generation gas purity sensors and analyzer based on Fiber Bragg gratings that can be used to monitor temperature, pressure, strain and gases, with the ability to put multiple optical signals on one fiber (also called multiplexing) for both sensing and data transmission. A Fiber Bragg grating is a pattern in the optical fiber that selectively reflects specific colors of light. Our photonics researchers, in conjunction with materials researchers from other GE-GRC labs, have developed Fiber Bragg grating sensors with “smart skin” on them, sensitive only to specific materials. These micron-sized fiber gas sensors can be used for determining hydrogen purity in a mixture of gases, for example, 90-100% range with 1% accuracy. Having this information about the fuel source available in real time (rather than traditionally existing gas chromatography and thermal conductivity detectors that have long processing times) vastly improves the process efficiency.
On the other hand, the same fiber sensors can be used to monitor the temperature and pressure in multi-parameter sensing systems for oil and gas exploration, or geothermal wells, along with other types of sensors, like a silicon micro-electromechanical (MEMs) sensor. The silicon MEMs sensor is a tiny vibrating mechanical element whose frequency changes very precisely with surrounding pressure. We place this Si MEMS sensor at the bottom of a geothermal well 3 km deep, at more than 350 C and pressures of more than 4200 psi, and then use light through an optical fiber rather than electricity to drive it and read from it. This way we don’t have to worry about frying electronics in such hot environments.
On September 29 and 30, the Photonics Lab hosted its first Photonics and Optics Symposium at the Niskayuna campus, where invited speakers from GE businesses, in addition to academia, industry and government discussed the science, technology and business of photonics and optics. In addition to the cool (or hot!) applications above that we discussed at the symposium, are there other ideas you’d like us to think about?