Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator

Mykhaylo Dubov, Vladimir Mezentsev, Ian Bennion

Research output: Contribution to conferencePaper

Abstract

Recent results on direct femtosecond inscription of straight low-loss waveguides in borosilicate glass are presented. We also demonstrate lowest ever losses in curvilinear waveguides, which we use as main building blocks for integrated photonics circuits. Low-loss waveguides are of great importance to a variety of applications of integrated optics. We report on recent results of direct femtosecond fabrication of smooth low-loss waveguides in standard optical glass by means of femtosecond chirped-pulse oscillator only (Scientific XL, Femtolasers), operating at the repetition rate of 11 MHz, at the wavelength of 800 nm, with FWHM pulse duration of about 50 fs, and a spectral widths of 30 nm. The pulse energy on target was up to 70 nJ. In transverse inscription geometry, we inscribed waveguides at the depth from 10 to 300 micrometers beneath the surface in the samples of 50 x 50 x 1 mm dimensions made of pure BK7 borosilicate glass. The translation of the samples accomplished by 2D air-bearing stage (Aerotech) with sub-micrometer precision at a speed of up to 100 mm per second (hardware limit). Third direction of translation (Z-, along the inscribing beam or perpendicular to sample plane) allows truly 3D structures to be fabricated. The waveguides were characterized in terms of induced refractive index contrast, their dimensions and cross-sections, mode-field profiles, total insertion losses at both 633 nm and 1550 nm. There was almost no dependence on polarization for the laser inscription. The experimental conditions – depth, laser polarization, pulse energy, translation speed and others, were optimized for minimum insertion losses when coupled to a standard optical fibre SMF-28. We found coincidence of our optimal inscription conditions with recently published by other groups [1, 3] despite significant difference in practically all experimental parameters. Using optimum regime for straight waveguides fabrication, we inscribed a set of curvilinear tracks, which were arranged in a way to ensure the same propagation length (and thus losses) and coupling conditions, while radii of curvature varied from 3 to 10 mm. This allowed us to measure bend-losses – they less than or about 1 dB/cm at R=10 mm radius of curvature. We also demonstrate a possibility to fabricate periodical perturbations of the refractive index in such waveguides with the periods using the same set-up. We demonstrated periods of about 520 nm, which allowed us to fabricate wavelength-selective devices using the same set-up. This diversity as well as very short time for inscription (the optimum translation speed was found to be 40 mm/sec) makes our approach attractive for industrial applications, for example, in next generation high-speed telecom networks.
Original languageEnglish
Publication statusUnpublished - 12 Sep 2010
EventInternational Conference of Advanced Laser Technologies - Egmond aan Zee, Netherlands
Duration: 11 Sep 201016 Sep 2010

Conference

ConferenceInternational Conference of Advanced Laser Technologies
Abbreviated titleALT' 10
CountryNetherlands
CityEgmond aan Zee
Period11/09/1016/09/10

Fingerprint

oscillators
waveguides
pulses
borosilicate glass
insertion loss
micrometers
curvature
refractivity
gas bearings
fabrication
radii
integrated optics
polarization
wavelengths
lasers
repetition
hardware
pulse duration
optical fibers
high speed

Bibliographical note

© The Authors

Keywords

  • direct femtosecond inscription
  • straight low-loss waveguides
  • borosilicate glass
  • curvilinear waveguides
  • integrated photonics circuits
  • direct femtosecond fabrication
  • femtosecond chirped-pulse oscillator
  • high-speed telecom networks

Cite this

Dubov, M., Mezentsev, V., & Bennion, I. (2010). Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator. Paper presented at International Conference of Advanced Laser Technologies, Egmond aan Zee, Netherlands.
Dubov, Mykhaylo ; Mezentsev, Vladimir ; Bennion, Ian. / Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator. Paper presented at International Conference of Advanced Laser Technologies, Egmond aan Zee, Netherlands.
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Dubov, M, Mezentsev, V & Bennion, I 2010, 'Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator', Paper presented at International Conference of Advanced Laser Technologies, Egmond aan Zee, Netherlands, 11/09/10 - 16/09/10.

Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator. / Dubov, Mykhaylo; Mezentsev, Vladimir; Bennion, Ian.

2010. Paper presented at International Conference of Advanced Laser Technologies, Egmond aan Zee, Netherlands.

Research output: Contribution to conferencePaper

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T1 - Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator

AU - Dubov, Mykhaylo

AU - Mezentsev, Vladimir

AU - Bennion, Ian

N1 - © The Authors

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N2 - Recent results on direct femtosecond inscription of straight low-loss waveguides in borosilicate glass are presented. We also demonstrate lowest ever losses in curvilinear waveguides, which we use as main building blocks for integrated photonics circuits. Low-loss waveguides are of great importance to a variety of applications of integrated optics. We report on recent results of direct femtosecond fabrication of smooth low-loss waveguides in standard optical glass by means of femtosecond chirped-pulse oscillator only (Scientific XL, Femtolasers), operating at the repetition rate of 11 MHz, at the wavelength of 800 nm, with FWHM pulse duration of about 50 fs, and a spectral widths of 30 nm. The pulse energy on target was up to 70 nJ. In transverse inscription geometry, we inscribed waveguides at the depth from 10 to 300 micrometers beneath the surface in the samples of 50 x 50 x 1 mm dimensions made of pure BK7 borosilicate glass. The translation of the samples accomplished by 2D air-bearing stage (Aerotech) with sub-micrometer precision at a speed of up to 100 mm per second (hardware limit). Third direction of translation (Z-, along the inscribing beam or perpendicular to sample plane) allows truly 3D structures to be fabricated. The waveguides were characterized in terms of induced refractive index contrast, their dimensions and cross-sections, mode-field profiles, total insertion losses at both 633 nm and 1550 nm. There was almost no dependence on polarization for the laser inscription. The experimental conditions – depth, laser polarization, pulse energy, translation speed and others, were optimized for minimum insertion losses when coupled to a standard optical fibre SMF-28. We found coincidence of our optimal inscription conditions with recently published by other groups [1, 3] despite significant difference in practically all experimental parameters. Using optimum regime for straight waveguides fabrication, we inscribed a set of curvilinear tracks, which were arranged in a way to ensure the same propagation length (and thus losses) and coupling conditions, while radii of curvature varied from 3 to 10 mm. This allowed us to measure bend-losses – they less than or about 1 dB/cm at R=10 mm radius of curvature. We also demonstrate a possibility to fabricate periodical perturbations of the refractive index in such waveguides with the periods using the same set-up. We demonstrated periods of about 520 nm, which allowed us to fabricate wavelength-selective devices using the same set-up. This diversity as well as very short time for inscription (the optimum translation speed was found to be 40 mm/sec) makes our approach attractive for industrial applications, for example, in next generation high-speed telecom networks.

AB - Recent results on direct femtosecond inscription of straight low-loss waveguides in borosilicate glass are presented. We also demonstrate lowest ever losses in curvilinear waveguides, which we use as main building blocks for integrated photonics circuits. Low-loss waveguides are of great importance to a variety of applications of integrated optics. We report on recent results of direct femtosecond fabrication of smooth low-loss waveguides in standard optical glass by means of femtosecond chirped-pulse oscillator only (Scientific XL, Femtolasers), operating at the repetition rate of 11 MHz, at the wavelength of 800 nm, with FWHM pulse duration of about 50 fs, and a spectral widths of 30 nm. The pulse energy on target was up to 70 nJ. In transverse inscription geometry, we inscribed waveguides at the depth from 10 to 300 micrometers beneath the surface in the samples of 50 x 50 x 1 mm dimensions made of pure BK7 borosilicate glass. The translation of the samples accomplished by 2D air-bearing stage (Aerotech) with sub-micrometer precision at a speed of up to 100 mm per second (hardware limit). Third direction of translation (Z-, along the inscribing beam or perpendicular to sample plane) allows truly 3D structures to be fabricated. The waveguides were characterized in terms of induced refractive index contrast, their dimensions and cross-sections, mode-field profiles, total insertion losses at both 633 nm and 1550 nm. There was almost no dependence on polarization for the laser inscription. The experimental conditions – depth, laser polarization, pulse energy, translation speed and others, were optimized for minimum insertion losses when coupled to a standard optical fibre SMF-28. We found coincidence of our optimal inscription conditions with recently published by other groups [1, 3] despite significant difference in practically all experimental parameters. Using optimum regime for straight waveguides fabrication, we inscribed a set of curvilinear tracks, which were arranged in a way to ensure the same propagation length (and thus losses) and coupling conditions, while radii of curvature varied from 3 to 10 mm. This allowed us to measure bend-losses – they less than or about 1 dB/cm at R=10 mm radius of curvature. We also demonstrate a possibility to fabricate periodical perturbations of the refractive index in such waveguides with the periods using the same set-up. We demonstrated periods of about 520 nm, which allowed us to fabricate wavelength-selective devices using the same set-up. This diversity as well as very short time for inscription (the optimum translation speed was found to be 40 mm/sec) makes our approach attractive for industrial applications, for example, in next generation high-speed telecom networks.

KW - direct femtosecond inscription

KW - straight low-loss waveguides

KW - borosilicate glass

KW - curvilinear waveguides

KW - integrated photonics circuits

KW - direct femtosecond fabrication

KW - femtosecond chirped-pulse oscillator

KW - high-speed telecom networks

UR - http://www.ru.nl/alt10/

M3 - Paper

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Dubov M, Mezentsev V, Bennion I. Low-loss waveguides fabricated by femtosecond chirped-pulse oscillator. 2010. Paper presented at International Conference of Advanced Laser Technologies, Egmond aan Zee, Netherlands.