Edge-emitting lasers with short-period semiconductor/air distributed Bragg reflector mirrors

Yuan, Y.; Brock, T.; Bhattacharya, P.; Caneau, C.; Bhat, R.

doi:10.1109/68.593332

Cited by 62 publications

(21 citation statements)

References 11 publications

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“…Even though there are distributed feedback (DFB) or distributed Bragg reflector (DBR) 5,6 in the ends of the laser cavity, the overall mirror reflectivity still remains low. Recently several research groups 7,8,9 reported an alternative method to increase the mirror reflectivity of semiconductor lasers by introducing a short (but deep) stack of DBR grating consisting of multilayers of semiconductor materials and air. This is attractive since the large refractive index difference between semiconductor materials and air provides a very high reflectivity and reduces the length of cavity at the same time.…”

Section: Introductionmentioning

confidence: 99%

Focused Ion Beam Micromachining of GaN Photonic Devices

Chyr

Steckl

1999

MRS Internet j. nitride semicond. res.

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Ga+ and Au+ focused ion beams (FIB) are used to micromachine GaN films. The GaN micromachining has been studied at energies from 30-90 keV, incident angle from 0-30°, and number of repetitive scans from 10 to 50 scans. Trenches milled in GaN have vertical and smooth side-walls and very smooth bottoms. The micromachining rate was found to be fairly independent of ion dose, ranging from 0.4 to 0.6 µm3/nC for Ga+ and 1 to 2 µm3/nC for Au+. This translates into an effective yield of of 6-7 atoms/ion for Ga+ and 21-26 atoms/ion for Au+. This represents the highest direct FIB removal yield reported to date. We have also investigated the micromachining of GaN substrate material: c-face sapphire. Using FIB Ga+, sapphire has an effective yield of ∼2-2.5 atoms/ion, or approximately 1/3 of the GaN sputtering yield. For the materials investigated, we found the sputtering yield to be inversely proportional to the strength of the material chemical bond. We also describe the application of the FIB μmachining technique to the fabrication of small period Distributed Bragg Reflector (DBR) mirrors for a short cavity GaN laser structure.

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Section: Introductionmentioning

confidence: 99%

Focused Ion Beam Micromachining of GaN Photonic Devices

Chyr

Steckl

1999

MRS Internet j. nitride semicond. res.

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“…8 corresponds to the high reflection found here, which emphasizes the fact that these high-contrast structures have low losses when designed properly. Secondly, the other reported work on such deeply etched Bragg mirrors 3,4 uses ''standard'' laser material with a top cladding in excess of 1-m thickness, so the demands on the dry-etch process are considerably greater. Furthermore, and more importantly, Bragg mirrors with a high air fraction were used, so only a small part of the microstructure consists of waveguiding material.…”

Section: Discussionmentioning

confidence: 99%

“…1 Our semiconductor-air grating can also be regarded as the simplest realization of a photonic bandgap ͑PBG͒ structure 2 ͑or ''photonic crystal''͒, because it fulfills the requirements of high refractive index contrast and small (Ͻ100 nm) feature size that are essential for PBGs in two and three dimensions. Furthermore, this is one of the few examples [3][4][5][6] where a photonic microstructure has been created and successfully used in an active laser material. Ultimately, it will be possible to realize light-emitting devices where the active area is totally enclosed in a photonic crystal and will therefore have its emission characteristic radically altered; the high-reflectivity mirror described here is only a first, albeit very important, step towards this goal.…”

Section: Introductionmentioning

confidence: 99%

Photonic microstructures as laser mirrors

Krauss¹,

Painter

Scherer

et al. 1998

Opt. Eng

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Abstract. Deeply etched 1-D third-order Bragg reflectors have been used as mirrors for broad-area semiconductor lasers operating at 975-nm wavelength. From a threshold and efficiency analysis, we determine the mirror reflectivity to be approximately 95%. The design of the GaAs-based laser structure features three InGaAs quantum wells placed close (0.5 m) to the surface in order to reduce the required etch depth and facilitate high-quality etching. Despite the shallow design and the proximity of the guided mode to the metal contact, the threshold current density (J th ϭ220 A/cm 2 for infinite cavity length) and internal loss (␣ i ϭ9Ϯ1 cm Ϫ1 ) are very low. © 1998 Society of Photo-Optical InstrumentationEngineers. [S0091-3286(98)00404-8]

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“…Among these, focused ion beam (FIB) milling is a useful and flexible dry etching method with the advantages of maskless, directly writing for fine patterning [1][2]. By using FIB milling, flat end GaN facets with verticality <1°, room temperature pulsed lasing, reduction of threshold and increation of efficiency on FIB facet polished GaN-based LD were demonstrted [3][4][5][6].Recently, an alternative method to increase the facet reflectivity of laser diodes (LD) by introducing a short (but deep) stack of DBR grating consisting of thin semiconductor materials and air gap was reported [7][8][9]. This is very attractive since the large refractive index contrast between semiconductor materials and air provides a high reflectivity of DBR even though with a few pairs.…”

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confidence: 99%

The fabrication of GaN‐based optical cavity mirrors by focused ion beam milling

Ren

Zhang

et al. 2003

phys. stat. sol. (c)

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The study of focused Ga ion beam milling for making GaN-based cavity mirrors is presented. The FIB etching rate of GaN was found to be in the rang of 0.6 µm 3 /nC -0.43 µm 3 /nC. Three kinds of mirrors including polishing mirror, tilt mirror and nitride/air distributed Bragg reflection (DBR) mirror were fabricated. In particular, by using the transfer matrix method, the dependences of reflectivity and tolerance on the DBR Bragg order combination, number of DBR pair and nitride fill factor were calculated. To take trade-off between high reflectivity and enough tolerance, the combination of 3rd Bragg order of air gap and 5th Bragg order of semiconductor wall and three pairs were chosen. A deeply etched nitide/air DBR with vertical sidewall was obtained by focused Ga ion beam milling. Negative effects of the FIB on the etched GaN-based mirrors were also noticed. 1 Introduction According to the strong demand for the high capacity storage of information, the GaNbased shot wavelength laser diode (LD) becomes the most promising laser source in the application for next generation DVD. However, since the lack of lattice matched substrates, one of the big problems in the fabrication of GaN LD on C-sapphire substrate is in making a cavity mirror of cleaved facets. In fact it is difficult to provide lower roughness on sidewalls of nitride grown on sapphire. The additional problem is that the much lower refractive index of GaN-based materials results in a very low reflectivity at the interface of nitride/air. Theoretically, the highest value of reflectivity attains only 18% for the idea GaN-based facet. It therefore usually requires an additional coating of dielectric multiple films on the facets.A variety of dry etching techniques for making GaN-based LD mirrors has been employed. Among these, focused ion beam (FIB) milling is a useful and flexible dry etching method with the advantages of maskless, directly writing for fine patterning [1][2]. By using FIB milling, flat end GaN facets with verticality <1°, room temperature pulsed lasing, reduction of threshold and increation of efficiency on FIB facet polished GaN-based LD were demonstrted [3][4][5][6].Recently, an alternative method to increase the facet reflectivity of laser diodes (LD) by introducing a short (but deep) stack of DBR grating consisting of thin semiconductor materials and air gap was reported [7][8][9]. This is very attractive since the large refractive index contrast between semiconductor materials and air provides a high reflectivity of DBR even though with a few pairs. The most successful works are on LDs at longer wavelengths in the near infrared region [10]. Currently, Wang [11] fabricated

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Edge-emitting lasers with short-period semiconductor/air distributed Bragg reflector mirrors

Cited by 62 publications

References 11 publications

Focused Ion Beam Micromachining of GaN Photonic Devices

Focused Ion Beam Micromachining of GaN Photonic Devices

Photonic microstructures as laser mirrors

The fabrication of GaN‐based optical cavity mirrors by focused ion beam milling

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