Waveguides for nitride based quantum cascade lasers

Stattin, Martin; Berland, Kristian; Hyldgaard, Per; Larsson, Anders; Andersson, T. G.

doi:10.1002/pssc.201000987

Cited by 10 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different designs were considered to reduce the mode overlap with metal contacts, which is denoted as Γ m , in GaN devices . Reverse bias operation provides a simple solution to this problem.…”

Section: Losses In P‐n Doped Gan Wgs Designmentioning

confidence: 99%

“…Different designs were considered to reduce the mode overlap with metal contacts, which is denoted as Γ m , in GaN devices. [32,33] Reverse bias operation provides a simple solution to this problem. Since the p-n junction resistance is orders of magnitude higher than the p-layer and contact resistances, one may use very short metal contacts to reduce the optical loss.…”

Section: Metal Lossesmentioning

confidence: 99%

See 1 more Smart Citation

Reducing Optical Losses in GaN Waveguides – Toward an Electro‐Optic Phase Modulator

Westreich

Atar

Paltiel

et al. 2018

Physica Status Solidi (a)

View full text Add to dashboard Cite

In recent years, gallium nitride (GaN) has been investigated as a potential material for various integrated photonic devices. A key component of integrated photonic devices is a voltage‐controlled phase modulator in an optical waveguide (WG) design. To date, the main obstacles in the realization of such a device are significant optical losses that are related to various mechanisms. In this research, the main factors for optical losses in a GaN phase modulator are experimentally studied. The suggested design is based on a reverse‐biased p–n junction ridge WG scheme. The losses are determined mainly using the Fabry–Perot method at a wavelength of 1064 nm, which is important for high‐optical‐power applications. The contribution of the ridge waveguide wall roughness losses, the p‐doped layer absorption, and the metallic p‐contacts is evaluated. Based on these results, an optimized structure of an electro‐optical GaN phase modulator is proposed. The modulator voltage response is calculated while taking optical polarization effects into account.

show abstract

Section: Losses In P‐n Doped Gan Wgs Designmentioning

confidence: 99%

Section: Metal Lossesmentioning

confidence: 99%

Reducing Optical Losses in GaN Waveguides – Toward an Electro‐Optic Phase Modulator

Westreich

Atar

Paltiel

et al. 2018

Physica Status Solidi (a)

View full text Add to dashboard Cite

show abstract

“…Interlacing the gain stages are thin AlGaN transport layers that match the injection and extraction energies between adjacent gain stages. 1,16) For the optical simulations we model the gain region as a bulk AlGaN layer with the same composition as the average of the gain region. This reduces the modeling complexity and is not believed to introduce significant errors, considering the large difference between the optical wavelength (1.55 µm) and the thickness of the gain stages (≈ 5 nm) and transport layers (≈ 10 nm).…”

Section: Waveguide Designmentioning

confidence: 99%

“…21) In Ref. 16 we show that by using an off-center contact geometry, waveguides with metal induced losses below 10 cm −1 are possible. However, the off-center geometry may lead to non-uniform current injection and thereby reduced electrical injection efficiency.…”

Section: Introductionmentioning

confidence: 99%

ZnO/AlN Clad Waveguides for AlGaN-Based Quantum Cascade Lasers

Stattin¹,

Bengtsson²,

Larsson³

2013

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

Waveguide designs for AlGaN-based near-infrared quantum cascade lasers are proposed and analyzed using optical mode solvers. Because of the poor electrical conductivity, AlN is not a suitable cladding material for the AlN/GaN/AlGaN gain region. Instead we propose the use of ZnO as a conductive top cladding and to embed the gain region between AlGaN current injection and extraction regions so that an AlN substrate can be used as the lower cladding. We also examine the use of an AlN template on a SiC substrate and find that it can also provide sufficient mode confinement with negligible radiation loss into the SiC substrate. We identify a single mode ridge waveguide design with reasonable mode confinement (40%) and loss (39 cm −1).

show abstract

“…They hold the promise of extending the operational regime of quantum cascade (QC) lasers in both the near and the far infrared. [8][9][10][11] The latter are due to the large longitudinal-optical (LO)-phonon energy ω LO ∼ 90 meV. For wurtzite AlN/GaN structures grown in the c-plane direction, the band profile is distinguished by huge internal electrical fields.…”

Section: Introductionmentioning

confidence: 99%

Polarization-balanced design of heterostructures: Application to AlN/GaN double-barrier structures

2011

Self Cite

View full text Add to dashboard Cite

Inversion and depletion regions generally form at the interfaces between doped leads (cladding layers) and the active region of polar heterostructures like AlN/GaN and other nitride compounds. The band bending in the depletion region sets up a barrier that may seriously impede perpendicular electronic transport. This may ruin the performance of devices such as quantum-cascade lasers and resonant-tunneling diodes. Here we introduce the concepts of polarization balance and polarization-balanced designs: A structure is polarization balanced when the applied bias match the voltage drop arising from spontaneous and piezeolectric fields. Devices designed to operate at this bias have polarization-balanced designs. These concepts offer a systematic approach to avoid the formation of depletion regions. As a test case, we consider the design of AlN/GaN double-barrier structures with AlxGa 1−x N leads. To guide our efforts, we derive a simple relation between the intrinsic voltage drop arising from polar effects, average alloy composition of the active region, and the alloy concentration of the leads. Polarization-balanced designs secure good filling of the ground state for unbiased structures, while for biased structures with efficient emptying of the active region they remove the depletion barriers.

show abstract

Waveguides for nitride based quantum cascade lasers

Cited by 10 publications

References 12 publications

Reducing Optical Losses in GaN Waveguides – Toward an Electro‐Optic Phase Modulator

Reducing Optical Losses in GaN Waveguides – Toward an Electro‐Optic Phase Modulator

ZnO/AlN Clad Waveguides for AlGaN-Based Quantum Cascade Lasers

Polarization-balanced design of heterostructures: Application to AlN/GaN double-barrier structures

Contact Info

Product

Resources

About