ABSTRACT
Lasing emission at multiple wavelengths can be used in different sensing applications and in optical telecommunication. In this work, we report a six-wavelength distributed Bragg reflector (DBR) laser, emitting around 976 nm with six ridge waveguide (RW) structures, where individual DBR gratings are combined into a common front section. These six elements are individually addressable and biased one at a time for individual wavelength selection. The drawback of this RW combination is observable in spatial characteristics where higher-order modes are supported. We addressed this issue by using a master oscillator power amplifier (MOPA) system that combines the six-wavelength MO laser with a tapered PA. Through this configuration, the PA acts as a spatial filter of the MO beam, providing a nearly diffraction-limited beam with M1/e22<1.5. In addition, the described MOPA system provides output powers around 4 W with spectral single-mode operation, with up to 9.36 nm of thermal wavelength tuning. We believe that the described MOPA configuration can be used in different applications, such as absorption spectroscopy.
ABSTRACT
We present a hybrid microintegrated diode laser module developed for iodine spectroscopy on board a sounding rocket. The laser module is based on a master-oscillator-power-amplifier concept: an extended cavity diode laser serves as the master oscillator, and a ridge-waveguide semiconductor optical amplifier provides the power boost. The module's form factor and mass correspond to 12.5×7.5×2.3cm3 and 750 g, respectively. With an electrical power of 3.75 W supplied to the module, 570 mW of optical power is provided out of a polarization maintaining optical fiber at 1064.490 nm with a technical linewidth of 13 kHz (55 kHz) at a 1 ms (10 ms) time scale. The laser module has successfully passed vibration tests at a level of 8.8g R M S . A nominally identical module has recently been used to demonstrate, for the first time, precision iodine spectroscopy in space.
ABSTRACT
Tunable high-power diode lasers are key components in various established and emerging applications. In this work, we present a compact hybrid master oscillator power amplifier (MOPA) laser system. The system utilizes a tunable GaAs-based sampled-grating (SG) distributed Bragg reflector (DBR) laser as the master oscillator (MO), which emits around a wavelength of 970 nm in a single longitudinal mode with a spectral width below 20 pm. The SG-DBR laser consists of two SGs, each of which can be thermally tuned with microheaters. By tuning one of the two SGs, a discrete wavelength tuning of 21.1 nm can be obtained with a Vernier mode spacing of about 2.3 nm. By tuning both SGs, 23.5 nm of quasi-continuous tuning is obtained, with a mode spacing of about 115 pm. The coupling of the beam emitted by the MO into a tapered power amplifier provides an amplified output power in the watt range having a nearly diffraction-limited beam with a propagation factor of M1/e22=1.6. The combination of high power and wide wavelength tuning in a compact system makes this light source ideal for, among other things, nonlinear frequency conversion.
ABSTRACT
A DBR tapered diode laser in continuous wave operation was used to generate second-harmonic radiation at 589 nm in a PPMgO:LN ridge waveguide crystal. An optical output power of 0.86 W at an optical-to-optical and an electrical-to-optical efficiency of 42% and 11%, respectively, was achieved. The visible radiation was characterized by a spectral bandwidth ΔνFWHM of 230 MHz and a beam propagation parameter M1/e22 better than 1.1. The integration of such a system into a housing of a small footprint will enable a portable and highly efficient module featuring a visible output power in the watt-level range.
ABSTRACT
We demonstrate a compact system for single-pass frequency doubling of high-power GaN diode laser radiation. The deep UV laser light at 222.5 nm is generated in a ß-BaB2O4 (BBO) crystal. A high-power GaN external cavity diode laser (ECDL) system in Littrow configuration with narrowband emission at 445 nm is used as pump source. At a pump power of 680 mW, a maximum UV power of 16 µW in continuous-wave operation at 222.5 nm is achieved. This concept enables a compact diode laser-based system emitting in the deep ultraviolet spectral range.
ABSTRACT
A high-power external cavity diode laser (ECDL) system with narrowband emission is presented. The system is based on a commercially available high-power GaN laser diode. For the ECDL, a maximum optical output power of 400 mW in continuous-wave operation with narrowband emission is achieved. Longitudinal mode selection is realized by using a surface diffraction grating in Littrow configuration. A spectral width of 20 pm at 445 nm with a side-mode suppression ratio larger than 40 dB is achieved. This concept enables diode laser systems suitable for subsequent nonlinear frequency conversion into the UV spectral range.
ABSTRACT
A ridge-waveguide InGaAs/GaAsP laser, emitting up to 250 mW in a single lateral and longitudinal mode at a wavelength of 894 nm, is presented. The distributed feedback is provided by a second order grating, formed into an InGaP/GaAs/InGaP multilayer structure. Owing to the stable lasing frequency, the large side mode suppression ratio (> 40 dB) and small spectral line width (< 200 kHz) the diode laser is well suited for caesium D1 spectroscopy. This was verified by the measurement of the hyperfine structure of the D1 line.
