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Boris S. Ryvkin

Bio: Boris S. Ryvkin is an academic researcher from University of Oulu. The author has contributed to research in topics: Laser & Semiconductor laser theory. The author has an hindex of 11, co-authored 48 publications receiving 503 citations. Previous affiliations of Boris S. Ryvkin include Ioffe Institute & Saint Petersburg State University of Information Technologies, Mechanics and Optics.

Papers
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Journal ArticleDOI
TL;DR: In this article, a semiconductor laser with a strongly asymmetric waveguide structure and a relatively thick active layer is proposed and analyzed for the purpose of generating high-power single-optical pulses by gain switching.
Abstract: A semiconductor laser with a strongly asymmetric waveguide structure and a relatively thick (~0.1 mum) active layer, resulting in an extremely large equivalent spot size, is proposed and analyzed for the purpose of generating high-power single-optical pulses by gain switching. An improvement in obtainable single-pulse energies of about an order of magnitude over conventional laser structures is predicted.

81 citations

Journal ArticleDOI
TL;DR: In this article, the construction principles and performance of a pulsed time-of-flight (TOF) laser radar based on high-speed (FWHM$ 100 ps) and high-energy (sim$ 1 nJ) optical transmitter pulses produced with a specific laser diode working in an enhanced gain-switching regime and based on single-photon detection in the receiver is discussed.
Abstract: This paper discusses the construction principles and performance of a pulsed time-of-flight (TOF) laser radar based on high-speed (FWHM $\sim$ 100 ps) and high-energy ( $\sim$ 1 nJ) optical transmitter pulses produced with a specific laser diode working in an “enhanced gain-switching” regime and based on single-photon detection in the receiver. It is shown by analysis and experiments that single-shot precision at the level of 2…3 cm is achievable. The effective measurement rate can exceed 10 kHz to a noncooperative target (20% reflectivity) at a distance of $>\ 50\ \hbox{m}$ , with an effective receiver aperture size of $2.5\ \hbox{cm}^{2} $ . The effect of background illumination is analyzed. It is shown that the gating of the SPAD detector is an effective means to avoid the blocking of the receiver in a high-level background illumination case. A brief comparison with pulsed TOF laser radars employing linear detection techniques is also made.

55 citations

Journal ArticleDOI
TL;DR: A simplest saturable absorber, in the form of an unpumped section, is introduced into a Fabry-Perot semiconductor laser with a strongly asymmetric broadened waveguide structure incorporating a relatively thick active layer for suppression of trailing oscillations and a decrease in the optical pulse width compared to the uniformly biased structure.
Abstract: A simplest saturable absorber, in the form of an unpumped section, is introduced into a Fabry-Perot semiconductor laser with a strongly asymmetric broadened waveguide structure incorporating a relatively thick (80 nm) active layer. This allows for suppression of trailing oscillations and a decrease in the optical pulse width compared to the uniformly biased structure. Single optical pulses of ~80 ps full width at half maximum (FWHM) and ~35 W peak power (~3 nJ pulse energy, Eopt), practically without trailing edge oscillations, were experimentally achieved under room temperature conditions by absorber-assisted gain-switching, using pumping current pulses of ~1.3 ns FWHM and ~17 A amplitude. The laser emission has a narrow (13 degrees FWHM in the transverse direction) far field.

54 citations

Proceedings ArticleDOI
09 May 2001
TL;DR: In this paper, a two-gain-curve gain equalization model was proposed to explain the polarization switching in VCSELs, where the spin-flip dynamics played an essential role during the polarization switch.
Abstract: Due to the emission of light perpendicular to the surface of the quantum well and the usually symmetric vertical resonator there is a priori no intrinsic polarization anisotropy mechanism in VCSELs. Small residual strain explains the emission of linearly polarized light with a common orientation along [110] or [1–10] crystallographic directions. These two modes of linear polarization are strongly anti-correlated. Experimentally, polarization switching between them can be observed with increasing the injection current. It could happen from shorter to longer wavelength mode (type 1) or in the opposite way—from longer to shorter wavelength mode (type II). The polarization switching happens through a region of mode hopping or hysteresis. In the first case, the dwell time (the average time the laser spends in one mode) scales in several orders of magnitude. Thermal (carrier) effects influence the polarization behavior of VCSELs through the red (blue) shift of the gain maximum and through the dependence of the losses on the photon energy and temperature. Also, internal or external stress strongly affects the polarization behavior of VCSELs, giving rise to refractive index and gain anisotropy. In principle, one has to consider different gain curves for different orientation of the light polarization. Such two–gain–curve gain equalization model could explain type I polarization switching followed by type II polarization switching. In order an abrupt switch to exist, gain nonlinearities have to be taken into account. It is possible that the spin-flip dynamics is playing an essential role during the polarization switch. Finally, we show one straightforward implementation of polarization switching in VCSELs, e.g. reconfigurable interconnects.

53 citations

Journal ArticleDOI
TL;DR: In this paper, a multiple quantum well laser diode utilizing an asymmetric waveguide structure with a large equivalent spot size of ∼3μm was shown to give high energy (∼1 nJ) and short (∻100ps) isolated optical pulses when injected with <10 A and ∼1-ns current pulses realized with a MOS driver.
Abstract: A multiple quantum well laser diode utilizing an asymmetric waveguide structure with a large equivalent spot size of ∼3 μm is shown to give high energy (∼1 nJ) and short (∼100 ps) isolated optical pulses when injected with <10 A and ∼1-ns current pulses realized with a MOS driver. The active dimensions of the laser diode are 30 μm (stripe width) and 3 mm (cavity length), and it works in a single transversal mode at a wavelength of ∼0.8 μm. Detailed investigation of the laser behavior at elevated temperatures is conducted; it is shown that at high enough injection currents, lasers of the investigated type show low temperature sensitivity. Laser diodes of this type may find use in accurate and miniaturized laser radars utilizing single photon detection in the receiver.

42 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a review of efforts to increase ηE is presented and it is shown that for well-optimized structures, the residual losses are dominated by the p-side waveguide and nonideal internal quantum efficiency.
Abstract: High-power broad-area diode lasers are the most efficient light sources, with 90-μm stripe GaAs-based 940-980 nm single emitters delivering > 10 W optical output at a power conversion efficiency ηE(10 W) > 65%. A review of efforts to increase ηE is presented here and we show that for well-optimized structures, the residual losses are dominated by the p -side waveguide and nonideal internal quantum efficiency ηi . The challenge in measuring efficiency to sufficient precision is also discussed. We show that ηE can most directly be improved using low heat sink temperature THS with ηE(10 W) reaching > 70% at THS = -50 °C. In contrast, increases in ηE at THS = 25 °C require improvements in both material quality and design, with growth studies targeting increased ηi and reduced threshold current and design studies seeking to mitigate the impact of the p-side waveguide. “Extreme, double asymmetric” (EDAS) designs are shown to substantially reduce p-side losses, at the penalty of increased threshold current. The benefit of EDAS designs is shown here using diode lasers with 30-μm stripes, (in development as high beam quality sources for material processing). Efficiency increases of ~ 10% relative to conventional designs are demonstrated at high powers.

180 citations

Journal ArticleDOI
TL;DR: A 64×64-pixel 3-D imager based on single-photon avalanche diodes (SPADs) for long-range applications, such as spacecraft navigation and landing, consuming less than 100 mW.
Abstract: This paper describes a 64 $\times $ 64-pixel 3-D imager based on single-photon avalanche diodes (SPADs) for long-range applications, such as spacecraft navigation and landing. Each 60- $\mu \text{m}$ pixel includes eight SPADs combined as a digital silicon photomultiplier, a triggering logic for photons temporal correlation, a 250-ps 16-b time-to-digital converter, and an intensity counter, with an overall 26.5% fill factor. The sensor provides time-of-flight and intensity information even with a background intensity up to 100 MPhotons/s/pixel. The sensor can work in imaging (short range, 3-D image) and altimeter (long range, single point) modes, achieving up to 300-m and 6-km maximum distance with <0.2-m and <0.5-m precision, respectively, consuming less than 100 mW.

130 citations

Journal ArticleDOI
TL;DR: For the first time, the model for obtaining design criteria of polarization maintaining VCSELs by using a small relief grating is used and the possibility of comparing different configurations on the same footing is offered; in particular, the performances of dielectric and metal gratings will be evaluated.
Abstract: Vertical-cavity surface-emitting lasers (VCSELs) have become leading light sources in plenty of applications due to their good characteristics and low costs. There are, however, some features that need improvements; therefore, optimized or new designs ideas are necessary. To this aim, an electromagnetic simulation tool, which is fast and precise at the same time, is desirable; to cover all the possible requirements, it should be fully three-dimensional (3-D) and vectorial. A model with such features was first proposed by Bava et al. ("Three-Dimensional Model for Vectorial Fields in Vertical-Cavity Surface-Emitting Lasers", Phys. Rev. A, vol. 63, p. 23816, 2001), based on coupled-mode theory. Here, a review of its applications will be given, related to particular devices: nonperfectly circular VCSELs and phase-coupled arrays. The comparison with the corresponding experimental results turns out to be very satisfactory. Therefore, we were encouraged to use the model for obtaining design criteria of polarization maintaining VCSELs by using a small relief grating. The capability of gratings to pin the VCSEL polarization was already demonstrated; however, the different configurations do not allow one to have a clear overview of this technique. Moreover, to the best of our knowledge, a full simulation of a VCSEL with a grating was never presented, due to the complexity of treating the corresponding fully 3-D and vectorial problem. For the first time, we have the possibility of comparing different configurations on the same footing; in particular, we will evaluate the performances of dielectric and metal gratings. With the design we propose here, single-transverse and single-polarization-mode operation are predicted with a suppression of the other polarization easily in the order of 45 dB.

68 citations

Book
01 Jan 1995
TL;DR: In this article, the authors present a detailed discussion of the properties of diode laser pulses and their applications in optical fiber communications, including the application of ultrafast diode Lasers in optical fibers.
Abstract: Basics of Semiconductor Lasers. Methods of Registration of Ultrashort Laser Pulses. Gain Switching and Q-Switching of Diode Lasers. Mode Locked Diode Lasers. Nonlinear Propagation Phenomena. Ultrafast Diode Lasers in Optical Fiber Communications. Applications in Picosecond Optoelectronics and Instrumentation. Future Trends and Conclusions.

67 citations

Patent
17 Nov 2014
TL;DR: In this article, the authors describe an apparatus that includes an assay chip that includes multiple pixels with sample wells configured to receive a sample, which, when excited, emits emission energy; at least one element for directing the emitted energy in a particular direction; and a light path along which the emission energy travels from the sample well toward a sensor.
Abstract: Apparatus and methods for analyzing single molecule and performing nucleic acid sequencing An apparatus can include an assay chip that includes multiple pixels with sample wells configured to receive a sample, which, when excited, emits emission energy; at least one element for directing the emission energy in a particular direction; and a light path along which the emission energy travels from the sample well toward a sensor The apparatus also includes an instrument that interfaces with the assay chip The instrument includes an excitation light source for exciting the sample in each sample well; a plurality of sensors corresponding the sample wells Each sensor may detect emission energy from a sample in a respective sample well The instrument includes at least one optical element that directs the emission energy from each sample well towards a respective sensor of the plurality of sensors

66 citations