Design and fabrication of highly dispersive semiconductor double-chirped mirrors

Jasik, A.; Dems, Maciej; Wnuk, Paweł; Wasylczyk, Piotr; Wójcik-Jedlińska, Anna; Regiński, K.; Zinkiewicz, Łukasz; Hejduk, K.

doi:10.1007/s00340-013-5662-4

Cited by 3 publications

(5 citation statements)

References 14 publications

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“…In the first analytical approximation, the structure is far from optimized. The minimum GDD is not less than −2000 fs 2 , and the mirror fabricated according to this design would be inferior to our previous-manually tuned-structures [4,5]. For the genetic algorithm, the exact properties of this initial structure are unimportant for the final optimized mirror.…”

Section: Resultsmentioning

confidence: 91%

“…After manufacturing, the reflectivity and GDD have been measured for both structures (Fig. 5) using the same setups and methods as in our earlier works [4]. As for the reflectivity, the position of the sharp reflectivity dip around 1050 nm can be used to match the calculated and experimental layer thicknesses, as the latter can be proportionally scaled at different locations on the wafer.…”

Section: Resultsmentioning

confidence: 99%

“…In the case of the high-dispersion Bragg mirrors three factors must be taken into account: (1) the maximum absolute value of the negative GDD that-for our mirror-was assumed to be at least −3000 fs 2 [4]; (2) the bandwidth in which this large negative GDD does not oscillate by more than 20 %; and (3) the average value of the mirror reflectivity over the low GDD band, which must not fall below 99 %. This leads to three components of the scoring function, each of which is multiplied by a certain weight.…”

Section: Numerical Design Methodsmentioning

confidence: 99%

“…From all the optimized results, two mirror structures were selected and fabricated. Details of the epitaxial growth of the high-dispersion Bragg mirrors and their characterization may be found in [4,5,15]. The mirror structures were covered with a three-layer anti-reflective coating to avoid strong GDD oscillations, resulting from the intra-mirror cavity.…”

Section: Numerical Design Methodsmentioning

confidence: 99%

“…On the other hand, semiconductor chirped mirrors have lower refractive index contrast and, thus, require more DBR pairs, which allows to provide better separation of reflection of different wavelengths and makes it easier to tune constant negative GDD over a broader band. In our previous works [4][5][6] we have demonstrated tunable semiconductor double-chirped mirrors with negative dispersion for applications in femtosecond lasers operating near 1 µm. We have fabricated them using arsenide-based molecular beam epitaxy (MBE), and with intentionally introduced layer thickness spatial gradient, we were able to make the mirror properties (reflectivity and dispersion) tunable over an 80-nm range across the mirror surface.…”

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confidence: 99%

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Optimization of broadband semiconductor chirped mirrors with genetic algorithm

et al. 2016

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and high damage threshold. However, the high refractive index contrast results in low number of distributed Bragg reflector (DBR) pairs and, consequently, constant value of high negative GDD can be hard to achieve over a broad band (around 10 nm near the 1-µm wavelength) with such mirrors. On the other hand, semiconductor chirped mirrors have lower refractive index contrast and, thus, require more DBR pairs, which allows to provide better separation of reflection of different wavelengths and makes it easier to tune constant negative GDD over a broader band. In our previous works [4][5][6] we have demonstrated tunable semiconductor double-chirped mirrors with negative dispersion for applications in femtosecond lasers operating near 1 µm. We have fabricated them using arsenide-based molecular beam epitaxy (MBE), and with intentionally introduced layer thickness spatial gradient, we were able to make the mirror properties (reflectivity and dispersion) tunable over an 80-nm range across the mirror surface. We demonstrated tunable mode-locked femtosecond operation of an Yb:KY(WO 4 ) 2 diode-pumped laser oscillator at the 1035-nm wavelength.We obtained negative group-delay dispersion (GDD), necessary for the femtosecond laser operation in the soliton regime, by using a double chirp of the mirror stack that resulted in different wavelengths being reflected at different depths within the semiconductor stack. In our mirror design, we followed classical approach, using an analytical formula [7]. However, to apply this formula we had to make a number of approximations [8], which resulted in a non-optimal mirror design. Hence, we have decided to focus our research on using exact numerical solutions of Maxwell equations and to perform computer optimization in order to achieve a structure with lower mean GDD spanning over a wider bandwidth with reduced oscillations. AbstractGenetic algorithm was applied for optimization of dispersion properties in semiconductor Bragg reflectors for applications in femtosecond lasers. Broadband, large negative group-delay dispersion was achieved in the optimized design: The group-delay dispersion (GDD) as large as −3500 fs 2 was theoretically obtained over a 10-nm bandwidth. The designed structure was manufactured and tested, providing GDD −3320 fs 2 over a 7-nm bandwidth. The mirror performance was verified in semiconductor structures grown with molecular beam epitaxy. The mirror was tested in a passively mode-locked Yb:KYW laser.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Numerical Design Methodsmentioning

confidence: 99%

Section: Numerical Design Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Optimization of broadband semiconductor chirped mirrors with genetic algorithm

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Semiconductor Multilayer Nanometrology with Machine Learning

Kwak

Kim

2023

Nanomanuf Metrol

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We review the measurement methods and thickness characterization algorithms of semiconductor multilayer devices. Today’s ultrahigh-density, high-energy-efficient three-dimensional semiconductor devices require an iterative semiconductor layer-stacking process. Accurate determination of nanometer-scale layer thickness is crucial for reliable semiconductor device fabrication. In this paper, we first review the commonly used semiconductor multilayer thickness measurement methods, including destructive and nondestructive measurement methods. Next, we review two approaches for thickness characterization: model-based algorithms using a physical interpretation of multilayer structures and a method using data-driven machine learning. With the growing importance of semiconductor multilayer devices, we anticipate that this study will help in selecting the most appropriate method for multilayer thickness characterization.

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Continuously tunable Yb:KYW femtosecond oscillator based on a tunable highly dispersive semiconductor mirror

Wnuk¹,

Wasylczyk²,

Zinkiewicz³

et al. 2014

Opt. Express

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The optimized nonuniform growth process was used to achieve spatially dependent reflectivity and dispersions characteristics in a highly dispersive semiconductor mirror. The mirror, together with a semiconductor saturable absorber mirror (SESAM), was used to demonstrate a tunable femtosecond Yb:KYW oscillator. In the passive modelocking regime the laser could be continuously tuned over 3.5 nm spectral band around 1032 nm with high resolution, maintaining the average output power above 140 mW.

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Design and fabrication of highly dispersive semiconductor double-chirped mirrors

Cited by 3 publications

References 14 publications

Optimization of broadband semiconductor chirped mirrors with genetic algorithm

Optimization of broadband semiconductor chirped mirrors with genetic algorithm

Semiconductor Multilayer Nanometrology with Machine Learning

Continuously tunable Yb:KYW femtosecond oscillator based on a tunable highly dispersive semiconductor mirror

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