Powerful SLED opens up new applications
Singapore, August 31, 2004--A superluminescent light-emitting diode (SLED) developed by DenseLight Semiconductors emits 120 mW at 1550 nm, an order of magnitude greater than the output of conventional SLEDs. The emitter thus becomes suitable for uses such as biomedical imaging and surveillance.
Traditional broadband light sources such as amplified-spontaneous-emission (ASE) sources assembled from discrete components tend towards a larger footprint than SLEDs and a lower reliability from build-quality complications. ASE light sources are also inherently inefficient because they rely on an indirect light generation process via a high-power laser pumping through fiberoptic circuitry. In contrast, DenseLight's chip-based SLED delivers a clean and broadband spectrum through direct quantum processes within the semiconductor device.
"This order-of-magnitude increase in SLED output power can totally change the way broadband sources are used and deployed today, "said Etsuji Omura, DenseLight's vice president of engineering. "In many application areas like test and measurement, fiberoptic sensors, optical-coherence tomography, and communications, increased power can certainly extend the operating range of such systems. But beyond that, it is DenseLight's vision to excite and empower new applications in various industries." Omura names biomedical, homeland security, and environmental/industrial sensing as areas that can benefit from the high-power SLED.
Biomedical imaging
Optical-coherence tomography (OCT) is a noncontact medical-imaging technique that is used to obtain high-resolution pictures of tissue structures using reflected short-coherence light. SLEDs are the ideal light source used in such medical imaging equipment. Higher power SLEDs at long wavelengths (greater than 1300 nm) have been long awaited by OCT makers to allow deeper and higher-resolution pictures within the human body, as well as providing fast scans for real-time video images.
Homeland security
High-powered broadband light sources operating in the IR can be used for remote sensing of hazardous organic droplets and gases. More substances with greater accuracy can be detected if the light source is more powerful and capable of broader spectra. Such installations can be very useful in detecting abnormal patterns of biochemical presence in crowded indoor and outdoor events. On a broader front, the high-power SLED can be deployed in biosurveillance programs to detect adverse health events and improve public safety.
Environmental and industrial sensing
By offering both telemetry and multiparameter sensing capabilities, fiberoptic sensing systems can provide networked sensing intelligence to meet stringent demands of many critical environmental and industrial concerns. The DenseLight high-power SLED can increase the sensitivity and reach of fiber sensors that detect pressure, strain, and temperature. In addition, both the power and wide wavelength range allow many sensors on different wavelength channels to be multiplexed for multipoint/multiparameter sensing through an optical-fiber network for the distributed sensing of earthquakes, water levels, displacement of bridges and buildings, and so on.
Communications
In telecommunications (the traditional application for SLEDs), the new high-power emitter is well-suited to be a wavelength-spliced broadband light source in wavelength-division-multiplexing passive optical networks. The wide operating wavelengths of SLEDs can open up the entire long-wavelength communication channels of O, E, S, C, and L bands compared to the C or L band-limited ASE sources. It can practically increase the broadcast capability of optical line terminals and drive down per-channel costs to subscribers.