Key kinematic parameters in a low-loss power splitter written by femtosecond laser micromachining

Peyton, Roberto; Guarepi, Valentín Luis; Videla, Fabiàn; Torchia, G. A.

doi:10.1088/1361-6439/aaafe8

Cited by 9 publications

(7 citation statements)

References 22 publications

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“…When

θ > 0 °

, the bend angle is so large that radiation mode cannot be completely coupled back to the waveguide, and therefore, the normalised transmitted power is greatly decreased [21]. Some design techniques at low splice angles are considered in [22]. However, simulation shows that for ring design the constrain over the spice angle of

0.9 °

can be relaxed to

1.44 °

reducing the amount of segments.…”

Section: Resultsmentioning

confidence: 99%

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO ₃ by direct laser writing

Pagano

Presti

Peyton

et al. 2020

IET Optoelectronics

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The aim of this work is to design an integrated optical ring resonator to be implemented in LiNbO3 with a 2.5 mm radius and an operating wavelength of 1550 nm. Considering these ring parameters, a free spectral range of 71.54 pm and a quality factor of ∼5×105 were calculated. The authors apply results to improve the implementation of femtosecond laser writing in lithium niobate crystals. As it is well‐known finite difference time domain method requires large memory and time for processing circuits with large footprint (few square mm), in contrast, the beam propagation method allows to simulate large bends in a simple way. RSoft suite design tools commonly represent circles by closed polygons whose geometrical parameters are not optimised to obtain bending losses as least as possible, as suggested by coherent coupling theory. In this sense, the suitable determination of a splice angle (in this case 1.44°), shape and length for segments are key parameters in the ring design. For this purpose, an ad hoc software was implemented to overcome this drawback. In summary, a 250 sided polygon side showed a suitable coupling performance and established a new layout approach for middle range rings.

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“…When

θ > 0 °

0.9 °

can be relaxed to

1.44 °

reducing the amount of segments.…”

Section: Resultsmentioning

confidence: 99%

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO ₃ by direct laser writing

Pagano

Presti

Peyton

et al. 2020

IET Optoelectronics

Self Cite

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“…where A o is the overlapping area 25 and N i is the relation between the spot size and the distance among two consecutive pulses (v/f ). The ablation threshold fluence depends directly on the micromachining kinematic parameters, because it is a function of N i as is exhibited in Eq.…”

Section: A Ablation Thresholdmentioning

confidence: 99%

“…Therefore, if we show that δ * tends to zero for a large pulse number, then we can demonstrate that δ also tends to zero. Since N i is larger than 1 and using geometric models 25 , the mean width of the groove is given by…”

Section: Roughness Studymentioning

confidence: 99%

Phenomenological studies of femtosecond laser ablation on optical thin films for integrated photonics

Peyton

Guarepi

Videla

et al. 2020

Optics & Laser Technology

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In this work, for the first time of our knowledge, we present a well-supported procedure to fabricate ridge optical waveguides onto thin films of PLZT by femtosecond laser ablation. In order to achieve smooth guiding structures to guarantee good optical performance, we have studied the ablation threshold characteristics for different kinematic conditions of fs laser machining and also we have explored the different ablation regimens for several fluencies reached. Besides, we characterize the morphology and roughness of ridge waveguides through a modal and scattering loss analysis, for waveguides made with single and multiple scan. An innovative phenomenological model that relates the sidewall roughness to process parameters is proposed in this paper. Conducting this approach it is possible to extend the fabrication method of smooth guiding structures by fs micromachining to many optical thin films in order to develop integrated photonics devices addressed to different technological applications.

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“…These values were pre-set to guarantee an adequate writing fluency and obtain Type II guides within the material. 14 Taking into account the coupling study that we carried out, the waveguides should be single and double track. 9 A set of single track and 6 double track waveguides were recorded maintaining the same writing characteristics and only varying their distance between tracks (gap) for the second ones.…”

Section: Fabrication: Writing Processmentioning

confidence: 99%

Modeling of the refractive index profile of a femtosecond written waveguide in LiNbO3

Presti

Guarepi

Videla

et al. 2019

Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications XIII

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Femtosecond laser pulse systems allows to modify in a precise and permanent way the optical properties of a transparent materials. This process enables the direct writing of guiding structures in materials, commonly known as waveguides, which are the base for optical circuit fabrication.It is our interest to study the main characteristics of the waveguides manufactured by the laser micromachining technique. Here, an analysis of the resulting refractive index profile has been carried out. This characteristic is essential for the design and simulation of integrated optical circuits. In particular we have developed our research on the study of light coupling in a pair of type II waveguides made in Lithium Niobate (LiNbO 3 ).These experimental backgrounds provide us with elements to adjust and test the retrieved profile. Taking into account different distance between tracks and writing energies, it is well known that the coupling length changes and the coupling ratio too. Then this study allows us to reconstruct the refractive index profile according to its manufacturing conditions. Modeling of the refractive index distribution profile is a key parameter to perform beam propagation mode simulations (BPM) to achieve more realistic results. So, by means of this method it is possible to obtain a general procedure to describe the characteristics of these kinds of waveguides. As a model test, integrated waveguides were built to corroborate their light coupling. In a first stage it is designed through BPM simulations then it is manufactured in an X-cut LiNbO 3 crystal in order to check its operation according to the simulations carried out.

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Key kinematic parameters in a low-loss power splitter written by femtosecond laser micromachining

Cited by 9 publications

References 22 publications

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO ₃ by direct laser writing

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO ₃ by direct laser writing

Phenomenological studies of femtosecond laser ablation on optical thin films for integrated photonics

Modeling of the refractive index profile of a femtosecond written waveguide in LiNbO3

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Key kinematic parameters in a low-loss power splitter written by femtosecond laser micromachining

Cited by 9 publications

References 22 publications

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO 3 by direct laser writing

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO 3 by direct laser writing

Phenomenological studies of femtosecond laser ablation on optical thin films for integrated photonics

Modeling of the refractive index profile of a femtosecond written waveguide in LiNbO3

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Product

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Design conditions in the middle range for implementation of integrated ring resonators in LiNbO ₃ by direct laser writing

Design conditions in the middle range for implementation of integrated ring resonators in LiNbO ₃ by direct laser writing