Semiconductor ring laser
Encyclopedia
Semiconductor ring lasers (SRLs) are miniature ring laser
devices with potential applications in optoelectronics
, photonics
and all-optical circuits. The first SRLs were developed in the 1980s. Recently, they have been of interest as potential random-access memory storage devices for all-optical computers.
Semiconductor ring lasers are literally ring-shaped optical waveguides with a lasing medium. They have the ability to trap light in a ring, and recirculate it continuously as long as they remain powered. The material of choice for SRLs is indium phosphide. SRLs can be square with corner reflectors, or, as is more common with the smaller designs, have a curved, "racetrack" shape. Devices are currently on the order of a 100 micrometre
s, but further miniaturization should be possible using existing silicon microelectronics technology.
In the summer of 2010 researchers Dr. Muhammad Maqbool and Kyle Main of Ball State University and Dr. Martin Kordesch of Ohio University were able to successfully develop the first Aluminum Nitride SRL on the order of 20 micrometers in diameter. This SRL was constructed by depositing a 4 micrometer thick semi conducting Aluminum-Nitride film doped with Ti+3 ions onto a stretched fiber optic cable of 12 micrometer diameter. This SRL was shown to have considerable gain and a low threshold pump power, making it a highly efficient laser system. The light was confined only to the film and did not reflect off of the outer surface of the optical fiber. Such an arrangement is called a "Whispering Gallery Mode" . Maqbool and Main plan to expand their work to include the development of nano scale SRL's on carbon nanotubes.
SRLs may serve as the basis of a new form of optical random access memory. The direction of circulation of light (clockwise or counterclockwise) would indicate the polarity of the bit (0 or 1). Due in part to the bistable and highly non-linear nature of the devices, they can be fed a starting signal from either direction. The directionality is maintained as long as the device remains powered. Other potential applications include "a digital response device that reshapes optical signals that have become distorted, effectively acting as a gate
." and a device for resynchronizing optical signals to eliminate timing "jitter".
A European research project formed in 2006 to study potential applications of SRLs. It is known as IOLOS, (Integrated optical logic and memory using ultra-fast micro-ring bistable semiconductor laser), and will receive funding of €1.25 million over three years. Intense Photonics and Siemens
are also providing a further €100,000.
Ring laser
A ring laser is a laser in which the laser cavity has the shape of a ring. Light in ring lasers has two possible directions of propagation: clockwise and counter-clockwise....
devices with potential applications in optoelectronics
Optoelectronics
Optoelectronics is the study and application of electronic devices that source, detect and control light, usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light...
, photonics
Photonics
The science of photonics includes the generation, emission, transmission, modulation, signal processing, switching, amplification, detection and sensing of light. The term photonics thereby emphasizes that photons are neither particles nor waves — they are different in that they have both particle...
and all-optical circuits. The first SRLs were developed in the 1980s. Recently, they have been of interest as potential random-access memory storage devices for all-optical computers.
Semiconductor ring lasers are literally ring-shaped optical waveguides with a lasing medium. They have the ability to trap light in a ring, and recirculate it continuously as long as they remain powered. The material of choice for SRLs is indium phosphide. SRLs can be square with corner reflectors, or, as is more common with the smaller designs, have a curved, "racetrack" shape. Devices are currently on the order of a 100 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s, but further miniaturization should be possible using existing silicon microelectronics technology.
In the summer of 2010 researchers Dr. Muhammad Maqbool and Kyle Main of Ball State University and Dr. Martin Kordesch of Ohio University were able to successfully develop the first Aluminum Nitride SRL on the order of 20 micrometers in diameter. This SRL was constructed by depositing a 4 micrometer thick semi conducting Aluminum-Nitride film doped with Ti+3 ions onto a stretched fiber optic cable of 12 micrometer diameter. This SRL was shown to have considerable gain and a low threshold pump power, making it a highly efficient laser system. The light was confined only to the film and did not reflect off of the outer surface of the optical fiber. Such an arrangement is called a "Whispering Gallery Mode" . Maqbool and Main plan to expand their work to include the development of nano scale SRL's on carbon nanotubes.
SRLs may serve as the basis of a new form of optical random access memory. The direction of circulation of light (clockwise or counterclockwise) would indicate the polarity of the bit (0 or 1). Due in part to the bistable and highly non-linear nature of the devices, they can be fed a starting signal from either direction. The directionality is maintained as long as the device remains powered. Other potential applications include "a digital response device that reshapes optical signals that have become distorted, effectively acting as a gate
Logic gate
A logic gate is an idealized or physical device implementing a Boolean function, that is, it performs a logical operation on one or more logic inputs and produces a single logic output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and...
." and a device for resynchronizing optical signals to eliminate timing "jitter".
A European research project formed in 2006 to study potential applications of SRLs. It is known as IOLOS, (Integrated optical logic and memory using ultra-fast micro-ring bistable semiconductor laser), and will receive funding of €1.25 million over three years. Intense Photonics and Siemens
Siemens
Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
are also providing a further €100,000.