Edge-emitting LEDs Research Articles

Handheld digital video code distributor using edge-emitting LED's and single mode optical fibers

This paper describes a handheld bandwidth-compressed digital NTSC picture code distribution system in which circuit configurations are simplified and made more inexpensive than MPEG2 distribution systems. The proposed system is constructed using edge-emitting LEDs (ELEDs) and single-mode (SM) fibers for distributing digital NTSC picture codes so as to easily distribute video signals from a video camera to video monitors installed in a video conference hall or in locations far from the camera. Using the handheld bandwidth-compressed digital NTSC picture code distribution system, a video signal can easily be distributed to the receivers installed in places far from the sender through SM optical fibers of 10 km even if a greater number of receivers is installed in the system.

Handheld digital video signal distributor using single mode optical fibers for video lecture hall application

This paper describes a handheld bandwidth-compressed digital NTSC picture code distribution system in which circuit configurations are simplified so that the proposed system is made more inexpensive than MPEG2 distribution systems. The proposed system is constructed using edge-emitting LEDs (ELEDs) and single-mode (SM) optical fibers for distributing digital NTSC picture codes so as to easily distribute video signals from a video camera to video monitors installed in a video conference hall or in locations far from the camera. Using the handheld bandwidth-compressed digital NTSC picture code distribution system, a video signal can easily be distributed to the receivers through SM optical fibers of 10 km.

Optical fiber digital transmission of multiplexed video and audio signals suitable for multimedia applications

This paper describes a new digital NTSC TV and audio signal transmission system in which circuit configurations are simplified and made more inexpensive than MPEG 2 on the basis of the subjective evaluation of the picture quality. An NTSC TV signal and an audio signal can easily be transmitted to the receiver at the same time, since the transmission rate is kept unchanged due to the insertion of the digital audio signal into the horizontal sync pulse of the digital NTSC TV signal. The proposed system has three features. Firstly, the system could give a satisfactory picture quality for consumer-use visual appliances even though the quality of the reproduced pictures is lower than that of the normal digital NTSC TV picture codes obtained at a sampling frequency of 4.00/spl times/fsc with a quantisation level of 8 bits. Secondly, the system can satisfactorily transmit NTSC TV picture codes at a low transmission rate of 50 Mbps even if such an advanced compression technique as MPEG 2 has not been used. Thirdly, the system is used for transmission of the digital audio signals which are inserted into the horizontal sync pulse of the digital NTSC TV signal. A combination of edge-emitting LEDs (ELEDs) and single-mode (SM) optical fibers enables the system to easily transmit a digital NTSC TV picture signal together with digital audio signals over a distance of 10 km through the SM optical fibers.

Handheld digital video code distributor using edge-emitting LED's and single mode optical fibers

This paper describes a handheld bandwidth-compressed digital NTSC picture code distribution system in which circuit configurations are simplified and made more inexpensive than MPEG2 distribution systems. The proposed system is constructed using edge-emitting LEDs (ELEDs) and single-mode (SM) fibers for distributing digital NTSC picture codes so as to easily distribute video signals from a video camera to video monitors installed in a video conference hall or in locations far from the camera. Using the handheld bandwidth-compressed digital NTSC picture code distribution system, a video signal can easily be distributed to the receivers installed in places far from the sender through SM optical fibers of 10 km even if a greater number of receivers is installed in the system.

Optical fiber transmission of data packets multiplexed with digital audio and video signals

Describes a system for transmitting data packets multiplexed with digital audio and NTSC TV signals using optical fibers. Up to 18 channels are allocated for data packets transmitted at a maximum speed of 1.764 Mbps. Digital audio signals are inserted into the horizontal sync period of the NTSC TV signal. In addition to data packet transmission, the digital NTSC TV signal transmission system is used to easily distribute many types of information classified into categories. The proposed system is characterized by: firstly, this system can give a satisfactory picture quality enough to operate it together with video equipment even though the quality of the reproduced pictures is lower than that of normal digital NTSC TV picture codes obtained at a sampling frequency of 4.00/spl times/fsc with a quantizing level of 8 bits. Secondly, NTSC TV picture codes, audio codes, and data packets can satisfactorily be transmitted using inexpensive devices at a transmission rate of as low as 50 Mbps. Thirdly, this system is used for transmitting data packets and audio signal codes which are inserted in the horizontal sync period of the digital NTSC TV signal. Both data packets and audio signal codes can be distributed to the specific receivers specified by device address. A combination of edge-emitting LEDs (ELEDs) and optical fibers enable the transmission system to easily transmit a digital NTSC TV picture signal together with data packets and digital audio codes. A new approach of combining ELEDs and optical fibers to distribute CATV pictures and electronic information via the ISDN is also proposed.

Linear, high-speed, high-power strained quantum-well LEDs

InGaAs/AlGaAs edge-emitting LEDs are shown to be efficient (4% quantum efficiency), linear over four decades of current, and capable of operating in a analog or digital mode at modulation bandwidths exceeding 500 MHz. The spectral width of these LEDs is on the order of 700 AA at the 3-dB intensity points. The device is suited for high-speed backplane and short-distance local area network applications, where fiber dispersion is inconsequential. It appears to be a competitive optical power source for a variety of advanced applications, with speed and power outputs approaching those of laser diodes, but without the complication of a threshold current and associated active stabilization circuitry. >

Laser and LED reliability update

The reliability of various types of InGaAsP/InP lasers and LEDs is reviewed with regard to failure modes and systems requirements. A systematic exposition, including the degradation modes that govern lifetime, is given. Optical transmission systems are reviewed in general terms. Surface-emitting LEDs and lasers are mainly discussed; edge-emitting LEDs are considered briefly. Degradation modes of optical devices and spectral aspects of reliability for distributed-feedback (DFB) lasers are described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

2 Gbit/s and 600 Mbit/s single-mode fibre transmission experiments using a high-speed Zn-doped 1.3 μm edge-emitting LED

High-speed heavily Zn-doped mesa-structure 1.3 μm edge-emitting LEDs have been developed for single-mode-fibre high-speed transmission. A 600 Mbit/s modulation without waveform equalisation, and a 2 Gbit/s modulation with equalisation, have been performed. At 2 Gbit/s, 9.8 km of single-mode-fibre transmission using the edge-emitting LED has been carried out for the first time.

Low-current 1.3 μm edge-emitting LED for single-mode-fibre subscriber loop applications

Index-guided InGaAsP edge-emitting LEDs couple 7 μW into single-mode fibre at a drive current of only 20 mA. These devices can be modulated at data rates in excess of 432 Mbit/s, and their operating characteristics are ideal for single-mode-fibre subscriber loop applications.

Bidirectional LED transmission on single-mode fibre in the 1300 and 1500 nm wavelength regions

Bidirectional transmission was demonstrated over 15 km of standard single-mode fibre using 1300 and 1500 nm edge-emitting LEDs at 140 Mbit/s and 45 Mbit/s, respectively. The bidirectional WDM filters, including two connectors, contributed 3.2 dB insertion loss in the 1300 nm channel and 2.6 dB in the 1500 nm channel. Spectral filtering introduced by the WDM devices reduced the dispersion penalty from 1.0 dB to 0.2 dB for the 1300 nm channel, and from 3.6 dB to 2.7 dB for the 1500 nm channel. The available system margins were 3.3 dB for the 140 Mbit/s channel and 8.0 dB for the 45 Mbit/s channel.

Transmission experiments at 560 Mbit/s and 140 Mbit/s using single-mode fibre and 1300 nm LEDs

Transmission at 560 Mbit/s has been demonstrated using single-mode fibre and LEDs at 1300 nm. Surface-emitting, edge-emitting and super-radiant LEDs were used to transmit over maximum distances of 4.5 km, 15 km and 25 km, respectively. At 140 Mbit/s, the corresponding distances achieved with the same set of LEDs are 7.5, 35 and 50 km. respectively.

High-power InGaAsP edge-emitting LEDs for single-mode optical communication systems

The letter describes 1.3 µm InGaAsP edge-emitting LEDs which couple 40 to 60 µW into a single-mode fibre. The 1.0 ns rise times and 30 to 45 nm spectral widths of these LEDs make suitable for optical communication systems operating at data rates as high as 400 Mbit/s.

Investigation on high speed CW edge-emitting LEDs grown on semiinsulating GaAs substrate : Bernhard Stegmuller and Helmut Grothe. Frequenz, 37 (4), 97 (1983)

Investigation on high speed CW edge-emitting LEDs grown on semiinsulating GaAs substrate : Bernhard Stegmuller and Helmut Grothe. Frequenz, 37 (4), 97 (1983)

Investigations on High Speed CW Edge-emitting LEDs Grown on Semiinsulating GaAs Substrate

Investigations on High Speed CW Edge-emitting LEDs Grown on Semiinsulating GaAs Substrate

High-power Ga(1-x)Al(x)As edge-emitting LEDs

High-power Ga_(1-x)Al_(x)As edge-emitting LEDs