Photonics: Integrated laser on silicon is looking good
A unique 'micro-loop mirror' design may enhance the performance of integrated laser on silicon
Active optical fibers with silicon photonic chips can carry a lot more information for data interconnect than copper cables. Silicon photonics can also be the material of choice for wiring 'lab-on-a-chip' devices — however, the construction of such devices is not without its challenges. One of the greatest difficulties is the implementation of lasers because silicon is a poor light emitter, but is commonly required for a photonic system on chip.
Doris Keh-Ting Ng at the A*STAR Data Storage Institute and co-workers have now successfully fabricated a laser on top of a silicon chip1. The III-V semiconductor materials are bonded to silicon to provide optical gain and the laser has a unique mirror design that promises enhanced device operation compared to the conventional feedback mirrors based on device facets.
“Integrated Si/III-V lasers can take advantage of low-loss silicon waveguides, while addressing the problem of low light emission efficiency that silicon devices typically have,” says Ng. Attaching a Si/III-V laser on top of silicon requires challenging fabrication techniques, and device performances can suffer as a result. Furthermore, any laser requires mirrors to maintain lasing action. Typically, such designs rely on the interface between air and the semiconductor, that is, the facets of the chip. These mirrors are not perfect and further reduce operation efficiency.
To improve on the latter aspect, the researchers have now come up with a unique mirror design, known as a micro-loop mirror (MLM). Light emitted from one end of the laser is guided along the waveguide, around a narrow bend and is then directed back into the device (see image). The mirror at the other end of the device is still formed by the interface with air, so that laser radiation can exit the device. The MLM achieves a remarkable 98% reflection efficiency of light. Such low losses mean that the MLM laser is comparatively efficient.
The successful demonstration of this technique is remarkable, considering that more than 30 fabrication steps are needed to fabricate the device, and in view of the fact that the MLM requires delicate and high-precision fabrication. The researchers aim to further enhance the laser, for example, by miniaturizing the device.
“Further improvements, for example, at the interface between the mirror and the lasing structure itself could lead to even better performance,” says Ng. “Laser with lower threshold and higher output power can possibly be achieved, leading to a potential solution to develop high-speed and low-cost optical communications and interconnects on electronics chips.”
Scanning electron microscope image of the silicon-based micro-loop mirror. Light entering the waveguide from the left is guided around the loop and redirected back into the laser structure. The inset shows the laser spot photographed with an infrared camera. Copyright : A*STAR
The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute
Lee Swee Heng | Research asia research news
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...