Showing papers on "Semiconductor optical gain published in 1976"

Return-beam-induced oscillations in self-coupled semiconductor lasers

Abstract: When a stripe-geometry heterostructure GaAlAs laser is irradiated by its own output beam, oscillations in the 1–100 MHz range are generated in the laser, and the frequency f of the oscillation varies with the length 2L of the optical path of the beam returned as f = α(c/2L), with α ≪ 1, where c is the velocity of light.

Half wave protection layers on injection lasers

Abstract: A body of semiconductor material of an injection laser device, capable of operating at a power level up to a few milliwatts per micrometer of emitting width, has two opposed facet surfaces. On at least one of the facet surfaces is a protection layer of an insulating material having an optical thickness equal to approximately one-half the vacuum wavelength of the optical radiation emitted by the device.

The inception of charge-coupled devices

Abstract: I T WOULD seem that the authors of the papers in this special issue have a very heavy responsibility. Much has been written about the mental processes that lead to innovation but this is one of the rare times that a group of people who themselves have participated in the act of innovati,on have been asked to shed some light on the factors which contributed to the generation of a new concept. It is not difficult to document the apparently important features; they have been told many times before. Indeed the telling and retelling with embellishments of “the day that etc.” gradually takes on a ring of authenticity that eventually becomes fact in itself. On this occasion, however, we shall try to analyze once again just exactly what did transpire, with the full understanding that with all the best effort at objectivity, it may still not be an accurate account of the subtle interplay between people that certainly played a most important role in our own work. The charge-coupled device concept is one that is basically a structure that called upon existing technology and was stimulated by the analogous work that preceded it in magnetic bubbles. All the ingredients necessary for the innovation were found within Bell Laboratories. The now well-known work at the Philips Eindhoven Laboratory by Sangster [l] and his colleagues on the Bucket Brigade was unknown to us. The importance of the Bucket Brigade as a member of the family of charge transfer devices is well recognized, and we want at this point to recognize the important contribution to device technology that has been made by the work a t Philips. In :late 1969, the device area of Bell Laboratories was strongly oriented towards innovation and exploratory development of new devices. Strong efforts were being directed towards such fields as IMPATT diodes, GaAs lasers, nonlinear optics, solid-state lasers, holography, Gunn diodes, magnetic bubbles, and the silicon diode array came.ra tube. Of particular interest was the work on magnetic bubbles. It was apparent that a radically new approach to signal processing was being brought into existence. Those of us who were working on semiconductor integrated circuits looked at the work in magnetic bubbles with some awe. In the magnetic bubbles it seemed that a new class of devices was in the offing in which there was a very natural and appealing way of storing and manipulating bits with a one-to-one correspondence to the digital format. It could. be argued that semiconductor integrated circuits, important as they were, had not yet broken away from the circuit concepts that had evolved through the use of dis-

Leaky wave diode laser

Abstract: A heterojunction diode laser which utilizes leaky wave coupling through a thin confining layer or a pair of thin confining layers to produce a high powered, highly collimated output beam with high external differential quantum efficiency, and relative freedom from facet damage resulting from high optical density.

Steady-state nonlinear stimulated emission from a laser with a distributed feedback

Abstract: A derivation is given of the equations describing steady-state stimulated emission from a laser with a distributed feedback which is ensured by interference, in the active medium, of two partly coherent optical pump beams. The threshold and output amplitude are calculated as a function of the pump rate and coherence, and the gain is found. It is shown that under certain conditions a laser of this kind can exhibit hard excitation conditions, which are of practical importance.

Investigation of the optical behaviour of GaAs lasers operated with pulse and sinusoidal modulation

Abstract: Investigation of the influence of pulse and sinusoidal modulation on the time-resolved laser spectra shows the existence of a time constant describing the optical transient behaviour. This time constant ranges from below 1 to more than 10 ns.

Formation, by penetrating radiation, of absorbing layers in the optical medium of a neodymium laser

Abstract: It is shown that coloration of optical media by penetrating radiation can be used to create absorbing layers in an optical laser medium. Special properties of these layers can be used to suppress the processes limiting the output energy and power of a laser.

Distributed Feedback GaAs/GaAlAs Diode Lasers

Abstract: Within the last few years GaAs/GaAlAs heterostructure laser diodes have been developed which are capable of continuous operation at 300°K and above for prolonged periods of time.(1-5) These lasers are suitable for a variety of uses including fiber optic communication, optical scanning, and writing of high density optical memories. However, in order to take full advantage of the small size and increase the utility of the devices in complex systems, it is desirable to be able to integrate these lasers into a monolithic optical circuit. The distributed feedback, a (DFB) laser presents just such an opportunity.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Spectroscopy With Visible And Far-Infrared Lasers

Abstract: A discussion of several spectroscopic techniques using two lasers for semiconductor impurity studies is presented The frequency of one laser is in or near the visible and the other in the far-infrared (10 to 100 microns) The second infrared laser offers several possibilities for spectroscopy in addition to the usual laser properties of high intensity, monochromaticity, and coherence For example, an infrared laser frequency can be selected which is resonant with or near a donor, acceptor, or exciton (intrinsic or bound) binding energy in a semiconductor The infrared laser then provides an intense and very precise probe, the effect of which may be studied in the fluorescence or absorption spectra produced by the visible laser This might be compared to a temperature dependent fluorescence study, with the difference being that a broad thermal effect is replaced by a sharp photodissociative or optical pumping effect produced by the infrared laser This has application to learning the role of specific impurities in recombination in devices such as an LED© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only