Stable dual-wavelength operation of InGaAs diode lasers with volume Bragg gratings

Abstract

Stable dual-wavelength operation of InGaAs diode lasers coupled with volume Bragg gratings has been demonstrated for the continuous wave and gain-switching regimes. Spectral narrowing down to 0.33nm has been realized with maximum output power of up to 1.85W from a broad area stripe laser diode in a single-grating external cavity configuration. Spectral separation from 0.5 (0.16THz)to6.5nm (2.05THz) has been obtained and an output power of up to 1.75W was achieved in dual-wavelength operation.

Multimodal spectral control of a quantum-dot diode laser for THz difference frequency generation

“…17). Using one LD and both VBG1 and VBG2 in series 16 and altering the LD gain current to give both GS and ES emission, simultaneous four wavelength output (at 1177/1182/1257/1262 nm) is also achievable, as shown in Figure 2(c). Spectral control of dual-modes is possible in a InGaAs/GaAs quantum well (QW) laser, 12 but the independent simultaneous spectral tuning at broadly separated spectral regions of a multi-QW laser designed for ultra-broadband spectral output may not be so straightforward, and one would expect a considerably lower electro optical efficiency.…”

“…1), the beam focus through the first VBG was altered slightly to accommodate an optimal focus over the two separate VBG's. 16 The two VBG windows were placed $25 mm apart in series and each was aligned independently. The cavity could be setup at effectively any length, in this case, the cavity was kept at 7 cm.…”

Dual-wavelength high-power diode laser system based on an external-cavity tapered amplifier with tunable frequency difference

“…In a few cases, broad-area diode lasers are used as gain device, and more than 1.7 W output power has been achieved with fixed frequency difference [16,17]. Due to the broad emitting aperture of broad-area diode lasers in the slow axis, these dualwavelength diode laser systems suffer from poor beam quality in the slow axis.…”

“…The monolithic dual-wavelength diode lasers show stable dual-wavelength operation, but the frequency difference of the two wavelengths is not tunable or the tuning range is limited, and the output power from the monolithic dual-wavelength diode lasers is normally less than 500 mW [8]. Different external-cavity feedback techniques have been developed for dual-wavelength diode laser systems, and different frequency selective elements have been used in these dual-wavelength external-cavity diode laser systems, such as bulk diffractive gratings for the double-Littman and double-Littrow external-cavity techniques [11,12,15], dual-fiber Bragg grating [13], dual-period holographic element [14], and single-wavelength volume Bragg gratings or monolithic multiplexed Bragg grating [16,17].…”

“…Different techniques have been developed to achieve dual-wavelength operation of a diode laser system, and they mainly can be classified into two categories: (1) Monolithic dual-wavelength diode lasers [6][7][8][9][10], and (2) diode laser systems based on different external-cavity feedback techniques [11][12][13][14][15][16][17]. The monolithic dual-wavelength diode lasers show stable dual-wavelength operation, but the frequency difference of the two wavelengths is not tunable or the tuning range is limited, and the output power from the monolithic dual-wavelength diode lasers is normally less than 500 mW [8].…”