Continuous Wave THz System Based on an Electrically Tunable Monolithic Dual Wavelength Y-Branch DBR Diode Laser

Gwaro, Jared O.; Brenner, Carsten; Theurer, Lara Sophie; Maiwald, Martin; Hofmann, Martin R.

doi:10.1007/s10762-020-00676-4

Cited by 14 publications

(10 citation statements)

References 17 publications

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“…At 785 nm, an emission wavelength well-established for Raman spectroscopy, corresponding dual-wavelength Y-branch distributed Bragg reflector (DBR) diode lasers have been reported [4]. They have been successfully applied in Raman field experiments outside of a traditional laboratory environment [5] as well as in a proof-of-principle application study generating THz radiation within a range of 0.1 THz -0.3 THz [6]. The lasers consisted of two ridge-waveguide (RW) laser cavities with a single output.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Y-branch and multimode interference coupler-based dual-wavelength light sources around 785 nm

Müller,

Theurer,

Koester

et al. 2024

Novel in-Plane Semiconductor Lasers XXIII

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Diode laser-based dual-wavelength light sources are experimentally compared in individual and common operation. First, a Y-branch distributed Bragg reflector diode laser is presented. It consists of two laser cavities with a single output waveguide. The device provides 180 mW and dual-wavelength laser emission around 785 nm. The measured spectral widths and spectral distance are 20 pm and 0.6 nm, respectively. Resistors implemented next to the gratings allow changing the wavelength spacing within a range of 0.0 nm -1.7 nm. Lateral far field profiles show a strong modulation and a lateral shift of 1° between both far fields indicates beam steering. Second, a multimode interference coupler-based master oscillator power amplifier is presented. It provides 500 mW dual-wavelength laser emission. Within the available power range, spectral widths of 20 pm and nearly constant peak emission wavelengths are measured. In comparison to quasicontinuous wavelength tuning obtained for the Y-branch laser, the MMI MOPA enables non-continuous wavelength tuning. As an example, selected spectral distances of 0.0 nm, 0.5 nm, 1.0 nm, 1.5 nm, and 2.0 nm are demonstrated in individual operation. Beam steering is successfully eliminated. Near field widths of 5 µm and far field angles of 15° result in beam propagation ratios of M 2 = 1.2 at the 1/e 2 level in all operation modes. This enables easy beam shaping or efficient single-mode fiber coupling. Both devices are suitable for spectroscopic applications such as Raman spectroscopy and shifted excitation Raman difference spectroscopy as well as for the generation of THz radiation by photomixing.

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Section: Introductionmentioning

confidence: 99%

Comparison of Y-branch and multimode interference coupler-based dual-wavelength light sources around 785 nm

Müller,

Theurer,

Koester

et al. 2024

Novel in-Plane Semiconductor Lasers XXIII

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View full text Add to dashboard Cite

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“…At 785 nm, an emission wavelength well-established for Raman spectroscopy, Y-branch distributed Bragg reflector (DBR) ridge waveguide (RW) diode lasers with up to 200 mW of optical output power have been demonstrated [7]. They have been applied in Raman field experiments outside of a traditional laboratory environment [8] as well as in a proof-of-principle application study for the generation of THz radiation within a range of 0.1 THz -0.3 THz [9]. The lasers were based on two DBR RW laser cavities coupled into a common output waveguide using a Y-branch coupling section with S-bend shaped waveguides.…”

Section: Introductionmentioning

confidence: 99%

Monolithically integrated multimode interference coupler-based master oscillator power amplifier with dual-wavelength emission around 830 nm

Müller,

Koester,

Theurer

et al. 2024

J. Phys. Commun.

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A monolithically integrated dual-wavelength multimode interference coupler-based master oscillator power amplifier is presented. It consists of two shallowly etched, laterally separated ridge waveguide laser cavities as master oscillators with individual distributed Bragg reflector gratings as cavity mirrors. A deeply etched coupling section containing S-bend shaped waveguides and a multimode interference coupler is used to couple the laser emission of the master oscillators into a shallowly etched single waveguide serving as power amplifier. Changing the etch depth for the coupling section enables a compact device layout. In addition, increased radiation angles of modes not coupled into the power amplifier help to suppress beam steering, otherwise indicated by laterally separated far-field intensity distributions. The device provides 0.5 W of dual-wavelength emission around 830 nm in individual and common operation. As designed, both emission wavelengths are separated by 0.5 nm with spectral widths below 20 pm, limited by the spectral resolution of the spectrometer. Both peak wavelengths remain within spectral windows of 50 pm within the available power range. This enables full flexibility selecting operating points for applications such as shifted excitation Raman difference spectroscopy and the generation of THz emission by photomixing. The emission wavelengths can additionally be non-continuously tuned by applying a heater current to resistors implemented next to the distributed Bragg reflector gratings. As an example, selected spectral distances of 0.5 nm, 1.0 nm, 1.5 nm, and 2.0 nm are demonstrated. Near field widths of 5 µm and far field angles of 17° result in beam propagation ratios of 1.4 (1/e2) in all operation modes and enable easy beam shaping or optical single-mode fiber coupling.

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“…Tunable monolithic dual colour lasers often use a Yshaped geometry with two independently tunable resonator branches. Wavelength control may be employed with dis-tributed Bragg reflector (DBR) (Gwaro et al, 2020) or distributed feedback (DFB) (Surkamp et al, 2021) sections. Wavelength tuning of one or both sections can be realised by altering the refractive index by current induced heating or carrier density changes.…”

Section: Introductionmentioning

confidence: 99%

“…also a photoconductive antenna). At this receiver the THz signal is mixed with a reference signal that stems from the second part of the split laser output which has passed through a reference arm that mostly contains a variable delay stage for sampling (Gwaro et al, 2020). Alternatively, sampling can be performed by frequency tuning (Moon et al, 2014;Surkamp et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Y-shaped tunable monolithic dual colour lasers for THz technology

Brenner,

Surkamp,

Hofmann

2023

Adv. Radio Sci.

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Abstract. THz generation by difference frequency generation can be accomplished by many different laser systems. The most cost efficient and compact solution will be monolithic dual-colour lasers. Application of these lasers in THz metrology can suffer from several drawbacks like coupling between the modes, strong amplitude variations, low tuning capabilities, or a complicated growth process. We discuss the impact of these points for THz measurements and present a simple monolithic dual colour laser which can be used for material characterisations.

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Continuous Wave THz System Based on an Electrically Tunable Monolithic Dual Wavelength Y-Branch DBR Diode Laser

Cited by 14 publications

References 17 publications

Comparison of Y-branch and multimode interference coupler-based dual-wavelength light sources around 785 nm

Comparison of Y-branch and multimode interference coupler-based dual-wavelength light sources around 785 nm

Monolithically integrated multimode interference coupler-based master oscillator power amplifier with dual-wavelength emission around 830 nm

Y-shaped tunable monolithic dual colour lasers for THz technology

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