Showing papers in "IEEE Journal of Quantum Electronics in 1980"
NEC1
TL;DR: In this paper, the effects of external optical feedback on the semiconductor laser properties have been examined, i.e., return of a portion of the laser output from a reflector external to the laser cavity.
Abstract: Influences on the semiconductor laser properties of external optical feedback, i.e., return of a portion of the laser output from a reflector external to the laser cavity, have been examined. Experimental observations with a single mode laser is presented with analysis based on a compound cavity laser model, which has been found to explain essential features of the experimental results. In particular, it has been demonstrated that a laser with external feedback can be multistable and show hysteresis phenomena, analogous to those of non-linear Fabry-Perot resonator. It has also been shown that the dynamic properties of injection lasers are significantly affected by external feedback, depending on interference conditions between returned light and the field inside the laser diode.
2,462 citations
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TL;DR: The last volume of the Progress in Optics series as discussed by the authors contains seven chapters on widely diverging topics, written by well-known authorities in their fields, including laser selective photophysics and photochemistry, laser phase profile generation, laser beamforming, and laser laser light emission from high-current surface spark discharges.
Abstract: Have you ever felt that the very title, Progress in Optics, conjured an image in your mind? Don’t you see a row of handsomely printed books, bearing the editorial stamp of one of the most brilliant members of the optics community, and chronicling the field of optics since the invention of the laser? If so, you are certain to move the bookend to make room for Volume 16, the latest of this series. It contains seven chapters on widely diverging topics, written by well-known authorities in their fields. These are: 1) Laser Selective Photophysics and Photochemistry by V. S. Letokhov, 2) Recent Advances in Phase Profiles (sic) Generation by J. J. Clair and C. I. Abitbol, 3 ) Computer-Generated Holograms: Techniques and Applications by W.-H. Lee, 4) Speckle Interferometry by A. E. Ennos, 5 ) Deformation Invariant, Space-Variant Optical Pattern Recognition by D. Casasent and D. Psaltis, 6) Light Emission from High-Current Surface-Spark Discharges by R. E. Beverly, and 7) Semiclassical Radiation Theory within a QuantumMechanical Framework by I. R. Senitzkt. The breadth of topic matter spanned by these chapters makes it impossible, for this reviewer at least, to pass judgement on the comprehensiveness, relevance, and completeness of every chapter. With an editorial board as prominent as that of Progress in Optics, however, it seems hardly likely that such comments should be necessary. It should certainly be possible to take the authority of each author as credible. The only remaining judgment to be made on these chapters is their readability. In short, what are they like to read? The first sentence of the first chapter greets the eye with an obvious typographical error: “The creation of coherent laser light source, that have tunable radiation, opened the . . . .” Two pages later we find: “When two types of atoms or molecules of different isotopic composition ( A and B ) have even one spectral line that does not overlap with others, it is pos-
1,071 citations
TL;DR: In this paper, the steplike density-of-states of a quantum-well heterostructure can improve the operation of a semiconductor laser, which is explained in terms of the step-like density of states and the disturbed electron and phonon distributions in the quantumwell active regions.
Abstract: The various features peculiar to the operation of quantum-well semiconductor lasers are described and illustrated with data on single- and multiple-quantum-well Al x Ga 1-x As-GaAs heterostructures grown by metalorganic chemical vapor deposition (MO-CVD). Photo-pumped and p-n diode lasers (injection lasers) are described that are capable of continuous room temperature (CW 300 K) operation. The basic problems of carrier collection, thermalization, and quantum-well band filling are considered and have made clear the limits on single quantum-well laser operation and how these can be overcome with multiple quantum-well active regions. The idea that the steplike density-of-states of a quantum-well heterostructure can improve the operation of a semiconductor laser is shown to be valid. Also, it is shown that phonon participation in the operation of a quantum-well laser, which was not anticipated, is a major (even dominant) effect, with perhaps the phonon emission itself in the compact active region being stimulated. Besides the obvious freedom that quantum-well layers offer in how the active region of a semiconductor laser can be designed, quantum-well lasers are shown to exhibit a lesser sensitivity of the threshold current density on temperature, which is explained in terms of the step-like density-of-states and the disturbed electron and phonon distributions in the quantum-well active regions. Values as high as \sim437\deg C have been obtained for T 0 in the usual expression J_{th}(T) = J_{th}(0) \exp (T/T_{0}) . Since photopumped multiple-quantum-well MO-CVD Al x Ga 1-x As-GaAs heterostructures have operated as CW 300 K lasers with only 5-10 mW of photoexcitation (uncorrected for focusing and window losses, \lambda \sim 5145 A), it is suggested that quantum-well laser diodes can be made that will operate at ∼1 mA or even less excitation.
487 citations
TL;DR: In this article, a tunable laser operation has been obtained from the solid-state crystal alexandrite (BeAl 2 O 4 :Cr3+) over the continuous range from 701 to 818 nm.
Abstract: Wavelength tunable laser operation has been obtained from the solid-state crystal alexandrite (BeAl 2 O 4 :Cr3+) over the continuous range from 701 to 818 nm. The tunable emission was observed at room temperature and above in a homogeneously broadened, vibronic, four-level mode of laser action. In this mode the laser gain cross section increases from 7 \times 10^{-21} cm2at 300K to 2 \times 10^{-20} cm2at 475K, which results in improved laser performance at elevated temperatures. Efficient 2.5 percent, low-threshold (10 J) operation has been obtained with xenon-flashlamp excitation of the 6 mm diameter × 76 mm length laser rods. Output pulses of greater than 5 J and average power outputs of 35 W have been demonstrated, limited by the available power supply. The emission is strongly polarized E\parallelb , with a gain that is 10 times that in the alternate polarization. The 262 μs, room-temperature fluorescence lifetime permits effective energy storage and Q -switched operation. Tunable Q -switched pulses as large as 500 mJ have been obtained with pulsewidths ranging between 33 and 200 ns depending on the laser gain. Laser action has also been demonstrated on the high-gain ( 3 \times 10^{-19} cm2emission cross section) R line at 680.4 nm and is also polarized E\parallelb . This three-level mode is analogous to the lasing in ruby except that the stimulated emission cross section in alexandrite is ten times larger than for ruby.
398 citations
TL;DR: In this paper, a method for obtaining CW autocorrelation measurements of picosecond pulses is described which employs an audio loudspeaker driven at 30 Hz in one arm of the correlator to permit auto-correlation display at this frequency.
Abstract: Completely general and novel expressions are presented for n th-order fast or slow correlation functions, with or without background contributions, from which more specialized n th- and second-order auto-correlation functions are derived A straightforward method for obtaining CW autocorrelation measurements of picosecond pulses is then described which employs an audio loudspeaker driven at 30 Hz in one arm of the correlator to permit autocorrelation display at this frequency Results of the application of this device to measurements of the picosecond pulses from a CW synchronously mode-locked Rhodamine 6G dye laser are presented
297 citations
TL;DR: In this article, a tunable coherent infrared (IR) source is presented, which utilizes the sideband produced by modulational instability of an optical signal in a fiber which results from a combination of anomalous dispersion and the nonlinear Kerr effect.
Abstract: A new tunable coherent infrared (IR) source is presented. It utilizes the sideband produced by modulational instability of an optical signal in a fiber which results from a combination of anomalous dispersion and the nonlinear Kerr effect. The generated frequency is in proportion to the square root of the optical pump signal. A coherent IR signal is generated by extracting the sideband.
275 citations
TL;DR: In this paper, an optical linear amplifier repeater between electronically regenerating terminal repeaters and a preamplifier in front of a photodetector in an electronically regenerative repeater is discussed.
Abstract: Applications of semiconductor laser amplifiers in intensity modulated digital optical transmission systems were studied theoretically. An optical linear amplifier repeater between electronically regenerating terminal repeaters and an optical linear preamplifier in front of a photodetector in an electronically regenerating repeater are discussed. Both traveling-wave type and Fabry-Perot cavity type laser amplifiers are considered. The noise and error rate performance in these systems are evaluated using formulations for semiconductor laser amplifiers. The mean and variance in the optical amplifier output photons calculated by the photon master equation [1] is used to obtain the worst case variance in the equalized output voltage [2] for these systems. The required receiving power reduction from direct detection scheme by a preamplifier system and the repeater spacing expansion between two electronically regenerating terminals by an optical linear amplifier repeater system are delineated.
227 citations
TL;DR: In this article, a new method for controlling millimeter-wave propagation in semiconductor waveguides-optical control was demonstrated, and phase shifts as high as 300°/cm at 94 GHz were observed accompanied by less than 1 dB insertion loss.
Abstract: We have demonstrated a new method for controlling millimeter-wave propagation in semiconductor waveguides-optical control. Phase shifts as high as 300°/cm at 94 GHz were observed accompanied by less than 1 dB insertion loss. A theoretical model has been developed to account in detail for the observed behavior. Extension of this technique to ultra-fast switching and gating of millimeter-wave signals is also described. Millimeter-wave pulsewidths as short as 1 ns and variable to tens of nanoseconds can readily be obtained.
215 citations
TL;DR: A focused, 3 mW UV laser beam has been used to produce micrometer-sized chemical processes on solid surfaces as discussed by the authors, which are initiated by the photodissociatlon of a molecular gas in the vicinity of the gas-solid interface.
Abstract: A focused, ultraviolet (UV) laser beam has been used to produce micrometer-sized chemical processes on solid surfaces. These processes are initiated by the photodissociatlon of a molecular gas in the vicinity of the gas-solid interface. Depending on whether the active photofragment reacts with or is adsorbed on the solid, microetching or microdeposition occurs. Both the surface properties of the solid and the gas-phase kinetics contribute to the process localization. Metal alkyls and methyl halides have been used as parent molecules for deposition and etching, respectively. A focused, 3 mW UV laser is sufficiently intense to produce satisfactory rates for both processes. Several applications of this small-scale photochemistry to microelectronics have been investigated.
149 citations
TL;DR: The results described in this paper will provide the means for setting up easily reproducible secondary frequency standards in the8.9-12.3 \mu m wavelength band.
Abstract: The band centers, rotational constants, absolute frequencies, and vacuum wavenumbers for12C16O 2 ,13C16O 2 ,12C18O 2 ,13C18O 2 ,12C16O18O,14C16O 2 , and14C18O 2 have been simultaneously computed from 590 beat frequency measurements between pairs of adjacent 00\deg1-[10\deg0,02\deg0] I and II band CO 2 laser transitions. The input data included the 56 beat frequencies measured between adjacent12C16O 2 rotational lines by Petersen et al. The absolute frequencies are directly related to the cesium frequency standard via the 29 442 483.315 (0.025) MHz 10.18 μm I-R (30) and the 32 134 266.891 (0.024) MHz 9.33 μm II-R(10) transitions in12C16O 2 which were measured by Evenson et al. The results described in this paper will provide the means for setting up easily reproducible secondary frequency standards in the 8.9-12.3 \mu m wavelength band.
147 citations
TL;DR: In this article, a broadband LiNbO 3 waveguide directional coupler optical modulator was constructed by conventionaly Ti in-diffusion into a cut plate and measured the phase difference average value along the propagation directions.
Abstract: Fabrication methods for low drive voltage and broad-band LiNbO 3 waveguide directional coupler optical modulator are described. Optical waveguides were prepared by conventionaly Ti in-diffusion into LiNbO 3 c -cut plate. To obtain wide-band frequency response, traveling wave electrodes were used. Electrode characteristic impedance measured by time domain reflectometry method coincided well with the calculated value by conformal mapping. Measured electrode conductor losses followed square root of frequency. To reduce electrode conductor losses, asymmetric and 3-μm thick Al electrodes were used. Directional coupler optical modulator frequency response was analyzed, using the phase difference average value along the propagation directions. Calculated value by this method coincided well with measured value obtained by a swept frequency technique. The characteristics of this modulator at the 1.317-μm wavelength are as follows: 100 percent modulation voltage is 4 V, extinction ratio is 17 dB, optical insertion loss is 5.4 dB, 3-dB bandwidth is 3.6 GHz, and rise time is about 400ps.
TL;DR: In this paper, the error rate characteristics of various optical modulation-demodulation schemes are studied and a coherent optical transmission system is employed in place of the presently available amplitude-shift-keyed (ASK) baseband direct detection system.
Abstract: Error rate characteristics of various digital optical modulation-demodulation schemes are studied. The main concern is whether we can improve receiving power levels to achieve a prescribed error rate by employing a coherent optical transmission system in place of the presently available amplitude-shift-keyed (ASK) baseband direct detection system. The receiving power level reduction in various modulation-demodulation schemes is calculated by taking into account the optical carrier wavelength, data rate, photodetector performance, local oscillator power level, and number of levels in multilevel codes. The phase-shift-keyed (PSK) homodyne detection system requires the least receiving power. The improvement in the receiving power level compared to the conventional ASK baseband direct detection system is expected to be 16-22 dB at the carrier wavelength of \lambda_{c} = 0.5-3 \mu m, 31-36 dB at \lambda_{c} = 3-5 \mu m, and 35-40 dB at \lambda_{c} = 5-10 \mu m.
NEC1
TL;DR: In this paper, Grating multiplexers and isolators for 0.8 μm band employing micro-optic approach have been developed for increasing further the utility of and to expand the application of fiberoptic communications.
Abstract: As new optical devices for increasing further the utility of and to expand the application of fiber-optic communications, grating multiplexers and isolators have been developed for 0.8 μm band employing microoptic approach. The development of these devices is the subject of this paper. The devices have desirable features of small size, compactness, high optical performances, and high reliability. The grating multiplexer consists of a graded-index rod, a blazed reflection grating replicated onto the graded-index rod slanting facet or a wedge facet, and an input-output fiber array. Simple calculations have been done to determine necessary element parameters for a given channel spacing. Experimental results are presented for five-channel multiplexers devised using a SELFOC®lens. Around 3 dB insertion loss and less than -30 dB crosstalk have been obtained for about 35 nm channel spacing in overall device size of 18 \times 13 \times 50 mm. Faraday rotation optical isolators for 0.8 μm band have been miniaturized by employing an efficient paramagnetic glass Faraday rotator, a magnet with a through hole and a folded optics in the Faraday rotator. The path number in the folded optics has been optimized in terms of trading-off between the magnet size and the insertion loss. A 0.9 dB insertion loss including fiber coupling loss and 36 dB isolation have been obtained in overall device size of 24 \times 24.5 \times 42 mm. Results on the temperature and wavelength dependence of the isolation are also presented. In addition, fundamental properties of optical circulators for 0.8 μm band and optical isolators and circulators both for 1.3 μm band, developed as extended modifications of the optical isolators for 0.8 μm band, are briefly described.
TL;DR: In this paper, the authors investigated the temporal characteristics of a distributed feedback dye laser and showed that the feedback is provided by the gain modulation and that the effect of refractive index modulation is negligible.
Abstract: The temporal characteristics of a distributed feedback dye laser are investigated both theoretically and experimentally. It is shown that the feedback is provided by the gain modulation and that the effect of refractive index modulation is negligible. The solution of the coupled rate equations predicts the generation of picosecond pulses. The mechanism of short pulse formation is self Q -switching which differs fundamentally from mode locking. A novel experimental arrangement for pumping the distributed feedback laser is described which makes it possible to obtain transform-limited pulses even with a partially coherent pumping source such as the N 2 laser. The experimental results show excellent qualitative and satisfactory quantitative agreement with the computer solutions. A very simple and reliable method for generation of tunable, nearly transform-limited single pulses with 36 ps duration (FWHM) is demonstrated experimentally. The feasibility of picosecond and subpicosecond pulse generation in the entire visible and near IR region is discussed.
TL;DR: In this article, the physical properties related to the crystal growth and carrier transport are discussed in terms of both the design and the operating characteristics of detectors fabricated from this ternary alloy.
Abstract: Ga 0.47 In 0.53 As has been used to make fast (rt i_{D} A) and good quantum efficiency (η Q ext > 50 percent over the entire 1.0-1.7 \mu m region of the optical spectrum). The physical properties related to the crystal growth and carrier transport are discussed in this paper in terms of both the design and the operating characteristics of detectors fabricated from this ternary alloy. The results of our work show that Ga 0.47 In 0.53 As is a material well-suited to several important semiconductor device applications. A comparison to other semiconductor photodiodes shows that Ga 0.47 In 0.53 As is one of the most sensitive detectors available in the 1.0-1.7 \mu m wavelength region. One can expect repeater-free transmission in excess of 150 km at 100 Mbits . s-1using these detectors in a digital optical fiber link at the 1.55 μm low-loss ( \alpha dB . km-1) low-dispersion transmission window.
TL;DR: In this paper, a new class of metal ion lasers with significant CW output power in the UV (220-320 nm) and near IR (800-2000 nm) spectral regions is described.
Abstract: A new class of metal ion lasers with significant CW output power in the UV (220-320 nm) and near IR (800-2000 nm) spectral regions is described. In a hollow cathode discharge the upper laser levels are excited via charge transfer collisions between ground state buffer gas ions and ground state metal atoms. At the present stage of development, hollow cathode metal ion lasers are shown to be comparable in UV output power to rare-gas ion lasers but with lower threshold currents by a factor of more than twenty. Visible output powers are lower than rare-gas ion lasers. In the text we present device progress to date, measurements of important plasma parameters, and an outline of potential applications of hollow cathode metal ion lasers.
TL;DR: In this article, a hemispherical microlens is fabricated on the end of a single-mode fiber by an electric arc discharge technique, which improves coupling efficiency between InGaAsP lasers with buried heterostructure geometry and singlemode fiber.
Abstract: A hemispherical microlens is fabricated on the end of a single-mode fiber by an electric arc discharge technique. It improves coupling efficiency between InGaAsP lasers with buried heterostructure geometry and single-mode fiber. The lowest coupling loss of 2.9 dB is achieved with the optimum lens radius of 8.5 μm. This loss is 4.4 dB lower than that with a butt joint. Experimental results of coupling efficiency and alignment tolerances in coupling with different lens radii in the range of 3.5-17 \mu m are discussed in detail. The results are in good agreement with theoretical values derived by Gaussian beam and paraxial ray approximations.
TL;DR: In this article, an analytic solution for power transfer for structures whose shape has a particular functional form is provided for structures fabricated with Ti:LiNbO 3 channel waveguides.
Abstract: Mode coupling between local normal modes in branching and separating optical waveguides is treated. An analytic solution for power transfer is provided for structures whose shape has a particular functional form. Analytic results are compared to numerical calculations for linear branches. Numerical examples for the design of shaped structures fabricated with Ti:LiNbO 3 channel waveguides are given.
TL;DR: In this paper, a comparison of theory with experimental results for the transmission of flexible infrared waveguides fabricated from commercially available aluminum sheet is given, which may be used to predict the losses of FIT waveguiders in useful geometries.
Abstract: This paper gives a comparison of theory with experimental results for the transmission of flexible infrared waveguides fabricated from commercially available aluminum sheet. From this analysis, design equations are generated, which may be used to predict the losses of FIT waveguides in useful geometries.
TL;DR: In this article, the optical properties of inhomogeneous materials are clarified and a guide to solve a number of related scientific and engineering problems based on these studies is provided. But the authors do not discuss the practical application of these studies.
Abstract: As stated by the authors in the Preface, their intent in writing this book was “to clarify the newest studies of the optical properties of inhomogeneous materials and then to provide a guide to solve a number of related scientific and engineering problems based on these studies.” The totality of the book is tailored so as to meet just this end. The book, begins with an all too brief review o f the theoretical seattering models in the presence of absorption. This single drawback is somewhat compensated for by a rather complete, list of references at the end of the book to which the avid reader must repeatedly retreat. Based upon this model review, the remainder of the book addresses the practical application of ’ these various
TL;DR: In this article, a design method for a miniature optical lens tipped on a singlemode fiber end to improve power coupling from a semiconductor laser is described, and the optimum coupling conditions and the obtained coupling efficiency are represented in terms of laser beam and fiber parameters.
Abstract: A design method for a miniature optical lens tipped on a single-mode fiber end to improve power coupling from a semiconductor laser is described. The lens shapes studied are hemispherical, hemicylindrical, and hemiellipsoidal. The optimum coupling conditions and the obtained coupling efficiency are represented in terms of laser beam and fiber parameters. Preferable ranges of hemispherical and hemicylindrical lenses are classified according to the laser and fiber mode spot sizes. Fiber axis offset and tilt effects on coupling efficiency are also studied.
TL;DR: In this paper, the transmission characteristics of optical fiber connectors are analyzed in detail in order to calculate nonlinear distortions and noise due to instable speckle patterns, and the fluctuation amplitude of the transmission loss and its sensitivity, with respect to a wavelength shift of the laser source, are determined for coherent and partially coherent laser sources.
Abstract: The transmission characteristics of optical fiber connectors are analyzed in detail in order to calculate nonlinear distortions and noise due to instable speckle patterns. The fluctuation amplitude of the transmission loss and its sensitivity, with respect to a wavelength shift of the laser source, are determined for coherent and partially coherent laser sources. Nonlinear distortions due to fiber connectors yield a second-order harmonic distortion of typically -36 dB for a single-longitudinal mode injection laser, and typically -65 dB for a multimode laser. The noise performance has also been estimated for both low frequency and high frequency fluctuations.
TL;DR: In this paper, the small-signal FIR gain coefficients have been measured as functions of the relevant parameters for two transitions in CH 3 OH and three in CH 2 F 2.
Abstract: This study is an investigation of the FIR radiation amplification in CW laser excited gases so essential for a complete quantitative understanding of the FIR laser cycle. The small-signal FIR gain coefficients have been measured as functions of the relevant parameters for two transitions in CH 3 OH and three in CH 2 F 2 . The measurements, demonstrating the influence of coherent pumping have been compared to quantum-mechanical calculations of a three-level system, interacting resonantly with two coherent fields. The good agreement found between theory and measurements indicates the correctness of the theory in predicting the gain properties of the CW FIR lasers. Also FIR gain saturations have been measured directly and exhibit the expected features.
TL;DR: In this paper, the optical waveguide, fabrication procedure, major optical properties, and reliability of buried-heterostructure (BH) AlGaAs lasers are described, which are characterized by low threshold currents (10-20 mA), nearly symmetric beam profile, singlemode oscillation, high linearity, small relaxation oscillations, and long-term mode stability.
Abstract: The optical waveguide, fabrication procedure, major optical properties, and reliability of buried-heterostructure (BH) AlGaAs lasers are described. BH lasers are characterized by low threshold currents (10-20 mA), nearly symmetric beam profile, single-mode oscillation, high linearity, small relaxation oscillations, and long-term mode stability. Moreover, BH lasers with a buried optical guide provide CW output powers of 10-20 mW with an overall power conversion efficiency as high as 35 percent.
TL;DR: In this article, low dark current and low multiplication noise properties for an In 0.53 Ga 0.47 As/InP avalanche photodiode are described, and the diode is prepared with a light absorption layer and an InP avalanche multiplication region.
Abstract: Low dark current and low multiplication noise properties for an In 0.53 Ga 0.47 As/InP avalanche photodiode are described. The diode is prepared with an In 0.53 Ga 0.47 As light absorption layer and an InP avalanche multiplication region. The lowest dark current density of 5.2 \times 10^{-4} A/cm2is obtained at 90 percent of a breakdown voltage. Multiplication noise power is proportional to the 2.7th power of the current multiplication factor. Impact ionization coefficient by holes is larger by 2-3 times than that by electrons in
TL;DR: In this paper, the authors measured the locking frequency width and locking gain of an AlGaAs double-heterostructure laser with respect to locking frequency and gain, and the relation of the locking bandwidth versus the ratio of locked laser to injected power was consistent with the analysis on injection locking phenomena.
Abstract: Injection locking of an AlGaAs double-heterostructure laser was studied with respect to locking frequency width and locking gain. The relation of the locking bandwidth versus the ratio of locked laser to injected power was consistent with the analysis on injection locking phenomena by Adler. Measured maximum locking bandwidth was 3 GHz, when locking gain was 23 dB. The 40 dB maximum gain was observed with the 500 MHz locking bandwidth. By measuring the beat notes between two temperature-stabilized free running AlGaAs lasers, the linewidth was estimated as 10 MHz.
TL;DR: In this paper, an extensive study has been performed on a dye amplifier pumped by copper vapor lasers, which utilizes a transverse pumping configuration in which the dye flow, pump beam, and dye extraction beam are mutually orthogonal.
Abstract: An extensive study has been performed on a dye amplifier pumped by copper vapor lasers. The amplifier utilizes a transverse pumping configuration in which the dye flow, pump beam, and dye extraction beam are mutually orthogonal. The operating characteristics of the amplifier have been studied using four dye-solvent systems which span the wavelength range continuously from 560 to 690 nm. Optimum conversion efficiencies of 18-30 percent at output powers of 0.41-0.76 W have been measured from the four dyes at a 6 kHz pulse repetition rate. The efficiencies and output powers were limited only by the available copper laser pump power. Analytic expressions have been obtained for the amplifier power gain and efficiency using a rate equation treatment of the system dynamics. Excellent agreement is obtained between the predicted and measured amplifier gain characteristics for rhodamine 6G.
TL;DR: In this paper, it was shown that a certain fundamental limit applies to the accuracy of all optical rotation sensors which use laser light as a probe, and the same relationship is obtained from a spontaneous-emission noise formulation.
Abstract: We show that a certain fundamental limit applies to the accuracy of all optical rotation sensors which use laser light as a probe. We derive this fundamental rotation-rate uncertainty from the Heisenberg uncertainty relations and Glauber's minimum uncertainty states. The same relationship is obtained from a spontaneous-emission noise formulation. We present experimental data on a (nondithered) four-frequency ring laser gyroscope for which this limit is attained.
TL;DR: In this article, a high speed sampling technique using a cascade of optical waveguide interferometers driven by CW sinusoidal traveling or standing microwaves is proposed, where each interferometer multiplies the optical signal by a function closely approximated by ω, where ω is the frequency of its microwave drive.
Abstract: A high speed sampling technique is proposed using a cascade of optical waveguide interferometers driven by CW sinusoidal traveling or standing microwaves. Each interferometer multiplies the optical signal by a function closely approximated by \cos^{4} \omegat , where ω is the frequency of its microwave drive. A cascade of four interferometers with 2.6 V microwave drives at 10, 20, 40, and 80 GHz and a total length of 2 cm can sample an optical signal with 2 ps resolution and 50 ps between samples. The sampler might be used in a picosecond sampling oscilloscope or in experiments requiring a jitter-free train of identical pulses.
TL;DR: In this paper, the error rate characteristics of an AlGaAs laser preamplifier and Si photodiode scheme were studied at a data rate of 100 Mbits/s.
Abstract: Signal gain, saturation power, and noise bandwidth, which are important parameters determining preamplifier and linear repeater system performance [1], were measured for an AlGaAs Fabry-Perot cavity type laser amplifier. The unsaturated signal gain increases with the pumping level and a maximum signal gain as high as 27 dB is obtained near oscillation threshold. The saturation output power, at which the signal gain is decreased from the unsaturated value by 3 dB, is -6 to -8 dBm. The beat noise powers between signal and spontaneous emission components were measured. The error rate characteristics of an AlGaAs laser preamplifier and Si photodiode scheme were studied at a data rate of 100 Mbits/s. The experimental results on noise powers and error rate performance are in reasonable agreement with the theoretical analysis given in an accompanying paper [1].