Spectral filtering for time isolation of intensive picosecond optical pulses from a Q-switched laser diode

Vainshtein, Sergey N.; Kostamovaara, J.

doi:10.1063/1.368342

Cited by 19 publications

(8 citation statements)

References 9 publications

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“…It is worth noting, however, that such an exact agreement should rather be considered accidental, since the HEM spectrum should be determined by a highly complicated range of factors, including the non-homogeneous distribution of carrier density across the active layer at a high current (see Fig.1) and the associated local broadening of the gain spectrum. As for the regular shift of approximately 50 meV in the emission band for all the modes towards low photon energy with respect to the local bandgap values (along x), this obviously originates from the heavy doping of the semiconductor material (see the same spectral shift for the heavily doped active region in [6]). …”

Section: Spatial Mode Profilesmentioning

confidence: 92%

“…The switching delay of the LEM and HEM modes lies in the nanosecond range with respect to the leading edge of the current pulse, while the short-pulsing mode appears near the end of the trailing edge of the current pulse. Since this behavior resembles the Qswitching operation of SH laser diodes [6], we refer to the short-pulsing mode here as a Q-switching pulse, following the conventional terminology. The fairly high sensitivity of the lasing delay to diode temperature can be attributed to the properties of the heavily doped active region [6], in which the optical losses are closely dependent on the lattice temperature.…”

Section: Time-resolved Spectramentioning

confidence: 99%

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First observation of the short-pulsing Q-switching mode in a double-heterostructure laser diode without ion implantation

Vainshtein

Sverdlov²,

Shestak³

et al. 2002

SPIE Proceedings

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A double heterostructure (DH) laser has been developed and tested with the aim of achieving high-power picosecond optical pulses in the near-infrared range for use in advanced laser radars and other applications. The physical idea consists of achieving fast gain control by means of temporal evolution of the electric field in the active region. The gain is controlled by the variation in current due to transformation in the built-in electric field across the active region, provided that a high current density is used for pumping. This transformation broadens the carrier energy distribution in the active region, thus suppressing lasing until the current pulse stops. The resulting carrier accumulation causes an enlargement in the power of the short-pulsing Q-switching mode. One of the most important features of the laser structure is the placement of the electron injector well outside the two hetero-barriers forming the active region. Three transient lasing modes were observed simultaneously in this laser diode, with a maximum difference in wavelength as large as 60 nm. One of them, a 45 W/ 25 ps Q-switching mode which appears near the trailing edge of the current pulse, being spectrally separated from the other two. A significant further increase in the power of the Q-switching mode can be expected from an optimized laser structure with two parasitic modes completely suppressed. The new laser structure produces much more powerful picosecond pulses than are obtainable from gain-switched lasers and allows lasing wavelength control by means of bandgap engineering.

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Section: Spatial Mode Profilesmentioning

confidence: 92%

Section: Time-resolved Spectramentioning

confidence: 99%

First observation of the short-pulsing Q-switching mode in a double-heterostructure laser diode without ion implantation

Vainshtein

Sverdlov²,

Shestak³

et al. 2002

SPIE Proceedings

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show abstract

“…Thus development of a laser diode transmitter emitting optical pulses around 1 ns in duration with as high as possible (at least several dozen W) peak power is the challenging task for long-ranging high-precision radars, and the main problem consists in high-current nanosecond drivers. It is additionally worth noting that a reduction in optical pulse duration well below 1 ns is possible when pumping current pulse of the laser diode becomes comparable with lasing delay, and various gain-and Q-switching picosecond modes [9,10,11] can be in principle realized, and even submicron precision of the distance measurement was demonstrated for the distance of 700 m using femtosecond laser [12]. Those modes are used in laboratory practice or for low-power laser transmitters, but they are not very reliable when broad laser diode chips with intrinsic structure inhomogeneity make the stability and reproducibility of the laser transmitter problematic in serial production quantities.…”

Section: Introductionmentioning

confidence: 99%

Nanosecond Miniature Transmitters for Pulsed Optical Radars

Filimonov

Zemlyakov

Егоркин

et al. 2017

Lecture Notes in Computer Science

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The-state-of-the-art in long-distance near-infrared optical radars is utilization the laser-diode-based miniature pulsed transmitters producing optical pulses of 3-10 ns in duration and peak power typically below 40W. The bandwidth of the receiving channel nowadays exceeds 300MHz, and thus the duration of the optical pulses exceeding 3 ns is a bottleneck in the task of high practical importance, namely increase in the radar ranging precision. Nowadays the speed of the high-current drivers is limited by the speed of a semiconductor switch that is typically field-effect transistor or an avalanche switch. The last one provides faster switching, and development of new avalanche switches is very challenging and important task, but this is not the only factor limiting the transmitter speed. Here we show that not only the switch, but also parasitic inductance in the miniature assembly and type of the capacitor play very important role in solving the problem of long-distance decimeterprecision radar.

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“…Laser diodes with direct current pumping are ideally suited for all these requirements, except that only a few techniques can provide high peak power (~10-100 W) in a single picosecond-range pulse [3][4][5] . All the possible candidates are widestripe picosecond laser diodes, which require pumping with high-current (~10 2 A) pulses of a duration of a few nanoseconds.…”

Section: Introductionmentioning

confidence: 99%

High-repetition-rate current drivers for picosecond laser modules employed in high-precision laser radars and 3D vision

2003

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High-precision laser radars and 3D vision systems with millimetre resolution require high-power picosecond optical pulses from laser diodes with direct current pumping in order to satisfy the requirements of low price, compactness and high reliability. A new laser diode capable of generating~50 W / 20 ps optical pulses for such applications has been proposed recently, but one very important technical limitation for many industrial applications lies in its repetition rate, which is at present limited to~50 kHz. This limitation originates from the heat dissipation in the Si-based, high-current nanosecond avalanche transistors used for laser pumping. It is shown in the paper, by using the 2D semiconductor device simulator, that the heat generation is powerfully localized in the avalanche transistor structure during the switching-on stage, but that in spite of this the associated thermal dynamics permits a higher maximum repetition rate than that observed experimentally. Moreover, smart designing of the semiconductor layers and construction of the heat sink should allow the limitation to exceed 1MHz. The lower limit observed so far in the experiments is caused by the stage of the voltage recovery across the transistor and may be softened by advanced circuit design.

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Spectral filtering for time isolation of intensive picosecond optical pulses from a Q-switched laser diode

Cited by 19 publications

References 9 publications

First observation of the short-pulsing Q-switching mode in a double-heterostructure laser diode without ion implantation

First observation of the short-pulsing Q-switching mode in a double-heterostructure laser diode without ion implantation

Nanosecond Miniature Transmitters for Pulsed Optical Radars

High-repetition-rate current drivers for picosecond laser modules employed in high-precision laser radars and 3D vision

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