41 GHz and 10.6 GHz low threshold and low noise InAs/InP quantum dash two-section mode-locked lasers in L band

International audienceThis paper reports recent results on InAs/InP quantum dash-based, two-section, passively mode- locked lasers pulsing at 41 GHz and 10.6 GHz and emitting at 1.59 lm at 20°C. The 41-GHz device (1 mm long) starts lasing at 25 mA under uniform injection and the 10.6 GHz (4 mm long) at 71 mA. Their output pulses are significantly chirped. The 41-GHz laser exhibits 7 ps pulses after propagation in 60 m of a single-mode fiber. The 10.6-GHz laser generates one picosecond pulses with 545 m of a single-mode fiber. Its single side-band phase noise does not exceed -80 dBc/Hz at 100 kHz offset, leading to an average timing jitter of 800 fs

Placenta vasculature 3D printed imaging and teaching phantoms

Three-dimensional printing makes it possible to create patient-specific, complex anatomical geometries that can be used for training, teaching and surgical planning. The human placenta is a vital organ that transports nutrients from the mothers' uterine circulation to the fetus via a complex vasculature. Complications of the fetal vasculature are increasingly being imaged with ultrasound and treated before birth using invasive fetal therapy. There is a need for human placenta training phantoms such as placental anastomoses that occur in monochorionic twin pregnancy and can cause twin-to-twin transfusion syndrome and fetal death, if untreated. In this study we developed two phantoms based on the human placenta using 3D printing technology: an ultrasound imaging phantom and an anatomical teaching model.</p

Anatomically realistic ultrasound phantoms using gel wax with 3D printed moulds

Here we describe methods for creating tissue-mimicking ultrasound phantoms based on patient anatomy using a soft material called gel wax. To recreate acoustically realistic tissue properties, two additives to gel wax were considered: paraffin wax to increase acoustic attenuation, and solid glass spheres to increase backscattering. The frequency dependence of ultrasound attenuation was well described with a power law over the measured range of 3-10 MHz. With the addition of paraffin wax in concentrations of 0 to 8 w/w%, attenuation varied from 0.72 to 2.91 dB cm-1 at 3 MHz and from 6.84 to 26.63 dB cm-1 at 10 MHz. With solid glass sphere concentrations in the range of 0.025-0.9 w/w%, acoustic backscattering consistent with a wide range of ultrasonic appearances was achieved. Native gel wax maintained its integrity during compressive deformations up to 60%; its Young's modulus was 17.4 ± 1.4 kPa. The gel wax with additives was shaped by melting and pouring it into 3D printed moulds. Three different phantoms were constructed: a nerve and vessel phantom for peripheral nerve blocks, a heart atrium phantom, and a placental phantom for minimally-invasive fetal interventions. In the first, nerves and vessels were represented as hyperechoic and hypoechoic tubular structures, respectively, in a homogeneous background. The second phantom comprised atria derived from an MRI scan of a patient with an intervening septum and adjoining vena cavae. The third comprised the chorionic surface of a placenta with superficial fetal vessels derived from an image of a post-partum human placenta. Gel wax is a material with widely tuneable ultrasound properties and mechanical characteristics that are well suited for creating patient-specific ultrasound phantoms in several clinical disciplines

Tunable quantum-dot mode-locked monolithic laser

No abstract available

Fundamental and harmonic mode-locking with pulse repetition rate between 200 MHz and 6.8 GHz in a quantum-dot external-cavity laser

In this paper, we present our latest results achieved with a 1.27-μm QD-ECMLL based on a two-section superluminescent diode chip (total length of 4mm, 15% absorber-to-total-length ratio) and a 53% output coupler as an external cavity front facet with a total optical cavity length of 75 cm (the back facet, on the absorber side, is high-reflection coated). A record-low repetition rate of 200 MHz and record-low-3dB RF linewidth of -240 Hz from a QD-ECMLL are achieved under stable fundamental mode-locking (FML), with the forward current of 300 mA and reverse bias of 8 V at 20°C

Tunable quantum-dot mode-locked monolithic laser

No abstract available

High-power spectral bistability in a multi-section quantum-dot laser under continuous-wave or mode-locked operation

Wavelength bistability between 1245nm and 1295nm is demonstrated in a multi-section quantum-dot laser, controlled via the reverse bias on the saturable absorber. Continuous-wave or mode-locked regimes are achieved (output power up to 25mW and 17mW)

Erratum for 'Quantum-dot external-cavity passively mode-locked laser with high peak power and pulse energy'

An InAs quantum-dot external-cavity passively modelocked laser with an operation wavelength of 1.27 μm is demonstrated, based on a twosection quantum-dot superluminescent diode with bending ridge waveguide and a 96% output coupler. Stable modelocking with an average power up to 60 mW was obtained at a repetition frequency of 2.4 GHz. This performance corresponds to a 25 pj pulse energy obtained directly from the oscillator, which represents a 5 5-fold increase in pulse energy when compared to the current state-of-the-art for semiconductor lasers. At a repetition frequency of 1.14 GHz, picosecond optical pulses with 1.5 W peak power are also demonstrated, representing the highest peak power achieved from an external-cavity laser at the 1.3 μm waveband, without the use of any pulse compression or optical amplification