Semiconductor amplifiers and lasers with tapered gain regions

Walpole, J. N.

doi:10.1007/bf00411298

Cited by 196 publications

(77 citation statements)

References 69 publications

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“…The tapered resonant cavity has been widely adopted in near-infrared diodes [5][6][7][8] and midinfrared QCLs [9][10][11][12][13]. The introduction of the tapered region may affect the propagation of the fundamental mode of the light field, threshold current and output power of laser devices.…”

Section: Basic Properties Of a Tapered Thz Qclmentioning

confidence: 99%

Power Amplification and Coherent Combination Techniques for Terahertz Quantum Cascade Lasers

Xie¹,

Li²,

Wang³

et al. 2017

Quantum Cascade Lasers

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Power amplification and coherent combination are important ways to improve the output power and beam quality of single-mode terahertz quantum cascade lasers (THz QCLs). Up to date, the tapered waveguide is the most convenient way to amplify the power of THz QCLs. The self-focusing effect in tapered THz QCLs induces nonmonotonic behaviours of the peak power and far-field beam divergence, which lead to the existence of optimal structural parameters. The surface and lateral grating techniques have also been employed in tapered THz QCLs to further improve the spectral purity. For coherent combinations, the progress of facet-emitting phase-locked arrays of THz QCLs is still limited due to both the lack of the understanding of dynamics of coupled QCLs and the difficulties in designing high-performance coupled waveguides. We will briefly review the developments of coherent arrays of THz QCLs and present a design of monolithic QCL arrays with common coupled cavity to achieve the optical mutual injection, which may provide a new way for coherent combination of THz QCLs.

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Section: Basic Properties Of a Tapered Thz Qclmentioning

confidence: 99%

Power Amplification and Coherent Combination Techniques for Terahertz Quantum Cascade Lasers

Xie¹,

Li²,

Wang³

et al. 2017

Quantum Cascade Lasers

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“…high power, good beam quality and narrow spectral linewidth [8][9][10][11]. Frequency doubling of such lasers has been demonstrated at different wavelength regions [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

Tawfieq

Jensen

Hansen

et al. 2015

Optics Communications

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“…In this regard two relevant solutions, tapered lasers and Master Oscillator Power Amplifiers (MOPAs), have received special attention due to their relatively high output power and their near diffraction-limited beam quality [5][6][7]. Fig.…”

Section: Motivationmentioning

confidence: 99%

“…In the context of laser beams, the term brightness is typically employed instead of the radiance of the source. According to [5], the brightness B can be defined as:…”

Section: High Brightness Laser Diodesmentioning

confidence: 99%

“…Different approaches have been proposed in order to suppress the high order lateral modes: Unstable resonators [64], laser arrays [65], spatially modulated reflectivity [66], BA DFB [67], α-DFB [68], tapered lasers [5][6][7] and MOPAs [5,69,70]. In the following, only the two last approaches which are relevant for this work will be discussed.…”

Section: High Brightness Laser Diodesmentioning

confidence: 99%

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Emission characteristics of 1.5 um monolithically integrated master oscillator power amplifiers

Suárez¹,

Fernánda²

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The present work is a study of the emission characteristics of monolithic semiconductor Master Oscillator Power Amplifiers (MOPAs) relevant for their use in applications requiring simultaneously high brightness and high spectral purity semiconductor laser sources. Two types of laser devices with wavelengths ranging between 1540 nm and 1580 nm have been studied: Commercial two-section MOPAs and three-section MOPAs specially designed for their use as optical sources for Differential Absorption LIDAR. The spectral analysis of the behavior of the two-section MOPAs revealed the occurrence of undesired spectral instabilities in large ranges of driving conditions precluding their use in applications requiring stable and narrow linewidth emission. A detailed experimental analysis of the stable and unstable emission regimens has been complemented with a theoretical analysis using a Travelling Wave model. From both approaches the instabilities have been attributed to dynamic effects induced by the optical feed-back allowed by the unavoidable residual reflectivity of the front facet and mediated by self-and cross-heating effects. The three-section MOPAs have been demonstrated to be free of spectral instabilities in a large range of driving conditions. The operation of these devices under the modulation conditions required for the intended application has been demonstrated. Their emission characteristics under modulation have been analyzed paying special attention to the modulation induced spectral broadening. Evidence of a frequency modulation contribution to the broadening has been shown. The frequency modulation induced by the modulation amplitude has been attributed to the refractive index changes induced by the carrier density modulation, induced in turn by the modulating current.The work is structured in 6 chapters. In the introductory Chapter 1 the work is motivated and framed in the research line of the group. The potential of MOPAs for high brightness applications is illustrated in the case of three applications: free space optical communications, wind Lidar and Lidar for remote sensing of atmospheric gases. In Chapter 2 the main ingredients on laser diodes necessary for the proper understanding of the rest of the work are briefly summarized. The chapter includes a brief description of two concepts for increasing the brightness of semiconductor sources: tapered lasers and monolithically integrated MOPAs. A review of the state of the art in integrated semiconductor MOPAs is also included.The details of the two-section straight MOPAs and three-section bent MOPAs investigated in this work as well as a description of the experimental techniques used for their characterization are provided in Chapter 3. Specific relevance is given to the description of those set-ups and experimental techniques that were implemented or developed as a part of this work, such as the set-up for driving unmounted multi-section lasers and systematically recording the maps of the optical and Radio-Frequency (RF) spectra, the implementa...

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Semiconductor amplifiers and lasers with tapered gain regions

Cited by 196 publications

References 69 publications

Power Amplification and Coherent Combination Techniques for Terahertz Quantum Cascade Lasers

Power Amplification and Coherent Combination Techniques for Terahertz Quantum Cascade Lasers

Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

Emission characteristics of 1.5 um monolithically integrated master oscillator power amplifiers

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