High-Brightness Quantum Well Tapered Lasers Sumpf, B.; Hasler, K.-H.; Adamiec, P. ...
IEEE journal of selected topics in quantum electronics,
05/2009, Volume:
15, Issue:
3
Journal Article
Peer reviewed
High-power quantum well lasers with high brightness in the spectral range between 650 nm and 1080 nm will be presented. Improved layer structures with a narrow vertical far-field divergence down to ...angles of 15deg (full-width at half-maximum) were developed. For these layer structures, optimized tapered lasers were processed to achieve laterally a nearly diffraction-limited beam quality with beam propagation factors smaller than 2. Depending on the emission wavelength, the tapered devices reach an output power up to 12 W and a brightness of 1 GWmiddotcm -2 middotsr -1 .
The relative intensity noise (RIN) in a two‐section distributed Bragg reflector (DBR) tapered laser emitting around 1060 nm is being studied experimentally. By analyzing the RIN spectra, a resonance ...frequency and damping is obtained. Herein, the dependence of the resonance frequency and the maximum RIN at the resonance frequency is studied as functions of the ridge waveguide (RW) and tapered section currents independently. The low frequency RIN is approximately −162 dB Hz−1, and the RIN peak at currents providing high output power is as low as −154 dB Hz−1. The observed nonlinearity of the squared resonance frequency with the RW section current is attributed to carrier saturation. The measured high values of the resonance frequency, exceeding 2.5 GHz for RW currents higher than 100 mA at a tapered current of 3 A, indicate gain lever enhancement.
The relative intensity noise (RIN) of a two‐section distributed Bragg reflector (DBR) tapered laser emitting at 1060 nm is examined experimentally. Crucial parameters such as resonance frequency and damping are derived through spectral analysis. These findings reveal intriguing nonlinearity in the squared resonance frequency and showcase high resonance frequencies exceeding 2.5 GHz, suggesting gain lever enhancement.
A new compact and cost-effective instrument for dynamic characterization of ultrawide dynamic range photodetectors is presented. The instrument is an optical pulse shaper (OPS) which has been ...developed as a LIDAR echo emulator (LEE). It uses a single laser diode at 1064 nm, its corresponding driver, and arbitrary waveform generator (AWG), to generate two overlapping LIDAR echoes (short and long). A 60-dB difference between the maxima of the echoes is achieved with a full dynamic range of 100 dB. The LEE is designed to make possible the characterization of the detection chain of a spatial LIDAR which uses a high-dynamic range HgCdTe avalanche photodetector (APD) but can be reprogrammed to emulate any high-dynamic range terrestrial or space LIDAR application.
The results of the total ionizing dose (TID) and single event effect (SEE) tests on the contactless angular position sensor based on Hall effect are presented. The TID testing reveals that the ...devices are resistant to the gamma radiation exhibiting only a slight increase in the supply current, not more than 1 % of the initial values. In general, both the serial peripheral interface (SPI) output errors and analog output errors have recovered to their initial values after annealing at high temperatures. Only the biased sample with magnet showed a significant increase of the analog output error at higher radiation levels and did not return to its initial value, it remained about a 56 % higher. Nevertheless, the error is still within the limits for space application of the sensor. SEE tests were performed up to linear energy transfer (LET) levels of 67.7 MeV·cm 2 /mg and the sensors experienced neither single event latch-up (SEL) nor single event transient (SET). The upper limit of cross section for single event functional interrupt (SEFI) was found by Weibull fit as being 3.53 · 10 -6 cm 2 and the LET threshold was 15.1 MeV·cm 2 /mg. The SEFI rates were calculated by means of the CRÈME96 for geostationary orbit (GEO) and the orbit of the International Space Station (ISS). Calculations were performed for minimum solar and peak 5 minutes environment, and in the case of the ISS orbit also trapped particles and magnetic weather conditions were included.
A compact and cost effective NIR-VIS-UV lidar echo emulator (LEE) was designed and manufactured as a compact breadboard. The LEE is an application specific optical pulse shaper delivering a short ...lidar return (echo) in the ns range overlapped with a long lidar return in the µs range with a repetition rate from 100 Hz - 500 Hz. The short echo power levels are in the range from 0.2-200 nW, whereas the long echo powers from 0.1-25 pW. The coarse power tuning between the two kind of echoes is done using variable attenuators. LEE provides three operation modes: short echo, long echo, or both echoes overlapped. In the overlapping mode, the power difference between the echoes exceeds 60 dB.
We propose an integrated path differential absorption (IPDA) lidar system based on a hybrid master oscillator power amplifier (MOPA) and single photon counting detection for column-averaged ...measurements of atmospheric CO 2 . The random modulated continuous wave (RM-CW) approach has been selected as the best suited to the average output power obtained from hybrid and monolithically integrated MOPAs. A compact RM-CW IPDA lidar instrument has been designed and fabricated. High-sensitivity and low-noise single photon counting has been used for the receiver. Colocated 2-km horizontal trial path experiments with a pulsed system and in situ measurements were performed for comparison. The RM-CW IPDA lidar instrument shows a relative accuracy of the order of about ±10% or ±40 parts per million CO 2 concentration in absolute terms. The measurements qualitatively demonstrate the feasibility of CO 2 IPDA measurements with an RM-CW system.
High brightness, highly efficient tapered lasers emitting around 675 nm have been developed. The devices have a 500- μm-long straight section and a 1500-μm -long tapered section with a flare angle of ...3°. At a temperature of 25°C and a current of 1.5 A, the lasers emit an output power of nearly 1.2 W. The maximum conversion efficiency of 31% is reached at an output power of 1 W. The emitted beam is nearly diffraction-limited with a beam propagation ratio (second moments) of 2.2.
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