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Quantum Electronics, IEEE Journal of

Issue 11 • Date November 1981

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Displaying Results 1 - 16 of 16
  • [Front cover and table of contents]

    Publication Year: 1981 , Page(s): 0
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    Freely Available from IEEE
  • A sensitive fiber-optic Fabry-Perot interferometer

    Publication Year: 1981 , Page(s): 2168 - 2170
    Cited by:  Papers (6)  |  Patents (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (963 KB)  

    A Fabry-Perot interferometric sensor utilizing a single-mode optical fiber has been demonstrated, exhibiting a finesse of 18 and a sensitivity to phase modulation of 7.9 \times 10^{-7} rad/ \sqrt {Hz} at 1 kHz. View full abstract»

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  • Single mode operation of buried heterostructure lasers by loss stabilization

    Publication Year: 1981 , Page(s): 2196 - 2204
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2986 KB)  

    A loss-stabilized buried heterostructure (LSBH) laser is reported that is much simpler to grow than conventional BH lasers, but has similar, near ideal, laser characteristics. Typical lasers, which incorporate an optical guide have active stripe widths \approx 2.5 \mu m determined by the initial mesa etching, have a laser threshold of 25 mA, and exhibit stable single transverse mode operations up to 60 mA and higher currents. The simplicity in growth results from not attempting to grow a single mode guide by carefully choosing the composition of the regrown burying layers, but instead simply forming a multiple mode guide by growing a cladding layer with a high aluminum composition. The large index discontinuity between the layer and the central mesa and the roughness of the etched mesa walls cause losses when interface scattering couples light from the initial mode into other modes. The losses rapidly increase with the mode number and, we believe, provide the selection mechanism which causes the laser to operate in the lowest mode. Calculations show that the observed variations in mesa width of 0.3 μm over distances of 10μm are adequate to explain the observed lowest mode stability. View full abstract»

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  • Angular multiplexing for multichannel communication in a single fiber

    Publication Year: 1981 , Page(s): 2215 - 2224
    Cited by:  Papers (6)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3050 KB)  

    A concept of angular multiplexing of several communication channels in a relatively short step-index fiber is described. The angular dependence of the outgoing light flux and the temporal impulse response are calculated for slab waveguides and round fibers in terms of the fiber's length and the excitation conditions. Calculations of the inpulse response in the presence of mode coupling are based on a simple model which is found to be adequate for short fibers. Crosstalk levels are calculated by integrating the flux over the aperture of the detectors. Measurements of angular flux distribution, temporal impulse response, and crosstalk levels agree with theoretical prediction and validate the proposed concepts. To increase light levels, parallel excitation of each channel by several light sources is suggested and tested. Also, light collection efficiency is increased by employing lenses and annular mirrors to deflect and focus the light from each channel to small-area detectors. Given a 25 m long fiber with a coupling constant of 10-5rad2/m, it is possible to multiplex four channels with cross-talk of about -25 dB and information rates ranging from 109bits/s to 1010bits/s for each channel. View full abstract»

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  • Amplitude fluctuation in laser signal transmitted through a long multimode fiber

    Publication Year: 1981 , Page(s): 2228 - 2233
    Cited by:  Papers (1)
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    Theoretical investigation has been made on fluctuation in detected signal at the end of a multimode fiber. It has been predicted that the fluctuation is caused by oscillation frequency fluctuation of a laser diode in association with interference, taking place at the detector surface, among nonorthogonal axial Components of field vectors for different modes. The prediction has been confirmed using a two-mode fiber and multimode graded-index fibers, by measuring amplitude and frequency of the signal fluctuation at the output end of the fiber. A method to suppress the amplitude fluctuation has been proposed for transmission characteristics measurement on long fibers. View full abstract»

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  • A 200 W average power, narrow bandwidth, tunable waveguide dye laser

    Publication Year: 1981 , Page(s): 2245 - 2249
    Cited by:  Papers (1)
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    A planar waveguide dye laser, driven by commercial xenon flashlamps with an average power output of 200 W at 50 pulse per second (pps) is described. Due to the planar structure, a narrow bandwidth operation down to 10 GHz has been obtained with a single grating arranged at grazing incidence. With this configuration, high overall efficiency up to 0.6 percent has been obtained, partially due to energy conversion of the broad-band emission spectrum of the flash-lamps by circulating an appropriate dye solution between flashlamps and reflectors. View full abstract»

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  • [Back cover]

    Publication Year: 1981 , Page(s): 0
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    Freely Available from IEEE
  • Temperature dependence of threshold current in (GaAl)as double-heterostructure lasers with emission wavelengths of 0.74-0.9µm

    Publication Year: 1981 , Page(s): 2205 - 2210
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1920 KB)  

    The threshold-current variation with temperature has been measured for Ga1-xAlxAs double-heterostructure (DH) lasers with AlAs mole fraction in the active layer x of 0.08 and 0.2, and with several heterojunction step heights \Delta x . The threshold-temperature coefficient Jth(350 K)/Jth(300 K), which generally increases with decreasing \Delta x , is found to be larger for x = 0.2 than that for x = 0.08 at the same value of \Delta x , and also to be larger for the lasers with smaller effective electron diffusion length in the P cladding layer, in the case of x = 0.2 . These characteristics are well explained by a model of carrier leakage due to unconfined carriers in the active layer. It is confirmed by a good fit of the experimental results with the calculated values that the electron leakage in the \Gamma conduction band of the P cladding layer dominates for x \leq 0.1 , but the hole leakage in the N cladding layer increases with x and becomes comparable in magnitude with the electron leakage at x \sim 0.2 . View full abstract»

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  • Rate equation model for mid IR OPML having common pump and upper lasing level; Application to 12.8 µm emission from NH3

    Publication Year: 1981 , Page(s): 2238 - 2244
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2152 KB)  

    A five-state kinetic model has been used to obtain an analytical expression for the power output of an optically pumped molecular gas laser having a common pumped and upper lasing level. The theoretical estimates for the various operational parameters of an optically pumped NH3laser (like operating pressure range, optimum operating pressure, variation of these with NH3gain length, etc.) obtained from this model are in good quantitative agreement with experimental results. View full abstract»

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  • Temperature dependence of a burst-mode copper halide laser

    Publication Year: 1981 , Page(s): 2166 - 2167
    Cited by:  Papers (1)
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    Efficient burst-mode operation of a CuCl laser is obtained at an optimum temperature of 450° when the salt is loaded directly into the discharge tube. The results show that a uniform discharge can be achieved under burst-mode excitation at a much higher partial vapor pressure of a copper halide than can be tolerated in the double-pulse mode. View full abstract»

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  • Joint collision of electrons and photons with hydrogen atoms

    Publication Year: 1981 , Page(s): 2233 - 2237
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1408 KB)  

    Ab initio perturbation theory calculations for the excitation of the n = 2 state of a hydrogen atom by electron impact in the presence of a near resonant electromagnetic field are presented. Single photon near-resonance process is discussed. A significant increase in the excitation cross section for the atom is obtained by joint collisions with electrons and photons. View full abstract»

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  • Heavily-doped semiconductor lasers

    Publication Year: 1981 , Page(s): 2187 - 2190
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    A theoretical study of the effect of heavily doping the active layer of a semiconductor laser shows that the minority carrier density required to reach inversion decreases with increasing doping. Unfortunately, the minority carrier lifetime also decreases since there is a component of the recombination rate that is proportional to the doping density. It is found that for a dopant with a recombination rate coefficient K_{B}, 5E-10 cm3/s (Zn in GaAs), the inversion current density has a local minimum at zero doping, but decreases again for n-type doping above 1E18 /cm, and is one third of the zero value at 4E18 /cm. The value of KBfor other dopants and materials is unknown; however, for a dopant with a coefficient smaller than 5E-11 , the inversion current would be less than one tenth the zero value at 4E18 n-type, and would also decrease with the addition of p-type dopant. These results indicate that by heavily doping the active layer with the proper dopant, one might obtain both faster response and a lower threshold current, particularly with n-type dopants. View full abstract»

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  • Operation of a double heterojunction GaAs/AlGaAs injection laser with a p-type active layer in a strong magnetic field

    Publication Year: 1981 , Page(s): 2190 - 2195
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1976 KB)  

    Measurements of the energy shift of the laser emission and the threshold current of a double heterojunction GaAs/AlGaAs injection laser with a p-type active layer as a function of the magnetic field up to 25 T and at T = 6 K and 40 K are presented. A simple expression is derived for calculation of the maximum of the gain curve, which coincides with the energy of the laser emission as a function of the magnetic field and the electronic scattering time. From the experimentally observed shift of the laser emission and the calculated maximum of the gain curve as a function of the magnetic field values for the carrier density at threshold, and for the electronic scattering time in the active layer at both temperatures have been obtained. View full abstract»

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  • Integrated optical SSB modulator/frequency shifter

    Publication Year: 1981 , Page(s): 2225 - 2227
    Cited by:  Papers (71)  |  Patents (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1072 KB)  

    A novel light single-sideband modulator, or frequency shifter, of integrated optics structure is proposed. The operation was confirmed by constructing and testing the device using Ti indiffused LiNbO3waveguides. The first demonstration of frequency shifting was carried out at 2 GHz, and either the upper or lower single-sideband output without carrier was obtained. Conversion efficiency of -5 dB was achieved with input drive power of 730 mW. View full abstract»

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  • The effect of facet mirror reflectivity on the spectrum of single-mode CW constricted double-heterojunction diode lasers

    Publication Year: 1981 , Page(s): 2211 - 2214
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB)  

    In this paper we show that the spectral mode content of mode-stabilized constricted douhle-heterojunction lasers can be altered by changes in facet reflectivity. If the facet reflectivity is substantially reduced below the nominal value of 30 percent, then the lasers will exhibit multilongitudinal mode operation. Nearly planar-geometry lasers that show instabilities can be made to operate in a stable single mode by increasing the facet reflectivity to values above 50 percent. View full abstract»

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  • Gas phase approaches to the near millimeter wave source problem

    Publication Year: 1981 , Page(s): 2171 - 2187
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6640 KB)  

    The lack of appropriate sources of radiation in the spectral region between 100 GHz and 1000 GHz is a major impediment to the development of many otherwise advantageous systems and applications. Because the NMMW spectral region lies between the microwave region where classical electronic techniques are optimum, and the optical where laser and thermal sources are favorable, many approaches to the generation of NMMW radiation are viable. These include: 1) gas phase devices, 2) bulk solid-state devices, 3) junction solid-state devices, and 4) electron beam devices. This paper addresses the first of these categories, gas phase devices. These are complex and archetypically interdisciplinary. While this may make detailed understanding difficult, it also holds the promise of unexplored avenues and fruitful discoveries. Thus, we attempt in this paper to provide a fundamental basis for the understanding of these devices with the anticipation that such a basis will stimulate new ideas and further progress in the field. We discuss atomic and molecular energy levels, excitation and inversion mechanisms, chemical processes, existing devices, fundamental considerations, and avenues of inquiry that seem especially attractive. View full abstract»

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Aims & Scope

The IEEE Journal of Quantum Electronics is dedicated to the publication of manuscripts reporting novel experimental or theoretical results in the broad field of the science and technology of quantum electronics..

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Aaron R. Hawkins
Brigham Young University