InAs/InP (100) quantum dots in InP photonic integrated laser systems

Geen abstrac

Investigation into diode pumped modelocked ND based laser oscillators for the CLIC photoinjector system

The photo-injector system envisaged for the proposed CLIC linear e+-e- accelerator at CERN has a demanding set of specifications on output pulse structure, power and timing stability. This paper reports on results obtained with quasi-CW diode pumped laser oscillators with output stabilisation. A 300W 804nm diode array stack is used to side pump Nd:YLF (1047nm) crystals with 200μs pulses at 100Hz repetition rate. Using feedback from the laser output to control an acousto-optic loss modulator in the cavity, start-up spiking and Q-switched behaviour is suppressed. Preliminary results obtained on incorporation of a saturable absorbing mirror for passive modelocking are presented

Integrated extended-cavity 1.5-μm semiconductor laser switchable between self- and anti-colliding pulse passive mode-locking configuration

We present the first integrated linear extended-cavity passively mode-locked (PML) semiconductor laser in which the operating mode can be switched electrically between two configurations. The first configuration is where the saturable absorber (SA) is located next to the output coupler, the so-called anti-colliding pulse mode-locking (ACPML) scheme. The second is where the SA is next to the high reflectance mirror, the self-colliding pulse mode-locking (SCPML) scheme. The 7.5-GHz PML was used to demonstrate experimentally the theoretical prediction that placing the SA next to the output coupler leads to a significant improvement in the laser stability and quality of the optical pulses. The experimental results show that the ACPML scheme allows for more deeply saturated SA due to the increase of optical power in the SA. The measurements of the RF spectra and autocorrelation traces confirm the superiority of the ACPML design in terms of pulse stability and width over the SCPML design for a wide range of operating conditions. The linewidth of the beat tone at the repetition rate was reduced by more than 60 times, the measured minimal autocorrelation width improved from 22 to 7.5 ps and a 3 dB increase in average output power was achieved

Design of feedback insensitive InP ring laser

The optical isolators used to protect semiconductor lasers against optical feedback cannot be integrated. Therefore we propose to fabricate a laser that has a strongly reduced sensitivity to feedback. Simulations show that such a device can be realized by employing a ring laser in which the clockwise and counterclockwise modes are not coupled. To achieve unidirectional lasing, this work proposes to use an intra cavity weak optical isolator based on two phase modulators that are driven 90 degrees out of phase. Simulations show up to 3% of intensity feedback can be tolerated without any distinguishable effect on the laser light

Characterization of integrated electro-optically tunable cascaded filters for tunable laser purposes

In this contribution we present our results on the tunable arrayed waveguide gratings designed and fabricated to be used in a tunable ring laser structure in the 1600 to 1800nm range. To be able to tune the two cascaded filters over 100 to 200nm the wavelength dependent phase shifting in the phase shifters have been measured. With the knowledge of the wavelength dependency in the phase shifters we are able to tune the AWG over the full wavelength range

Experimental comparison of extended-cavity passively mode-locked 1.5 µm quantum well lasers with anti-colliding design and self-colliding design

In this paper we present an experimental verification of a prediction of significantly improved performance of an integrated passive mode-locked laser (PMLL) through the use of an anti-colliding (AC) design comparing with a self-colliding (SC) scheme. The most commonly used design is the linear SC cavity. In this scheme a saturable absorber (SA) is placed close to the high reflectivity facet, which allows the pulse to interact with itself within the SA. However in [1] it was shown theoretically that an AC design where the SA is placed next to the low reflectivity output coupler is advantageous. It leads to a higher stability, an increase of optical output power and shorter pulses due to the weaker saturation of the gain and enhanced modulation of the SA in comparison with symmetrical mode-locking (SML) and SC scheme. A marked improvement in the performance of two-section cleaved facet PMLLs was achieved by the introduction of a low-reflectance coating at the SA facet and a high-reflectance coating on the other facet in comparison with a non-coated device (SML configuration) in [2]. However, the deposition of the coatings may lead to changes in the reflection spectrum

Integrated dual-wavelength AWG laser for sub-terahertz wave generation

We present a monolithically integrated ring dual-wavelength semiconductor laser in which both wavelengths (¿1 and ¿2) are generated and amplified by the same semiconductor optical amplifier (SOA). An arrayed waveguide grating (AWG) is used as intra-cavity filter to combine the two wavelengths. The use of a Mach-Zehnder construction allows equalizing actively the power of ¿1 and ¿2 and tuning their frequencies. An analytical model is exploited to investigate the influence of crosstalk on the functioning of the device and to identify a calibration strategy. The device has been fabricated using active/passive integration technology on a standardized photonic integration platform

Widely tunable monolithically integrated lasers using intracavity Mach-Zehnder interferometers

Using monolithic integration technology we have designed and fabricated tunable lasers in the 1.5 µm region with a demonstrated tuning range of 60 nm and single mode operation. This performance is achieved using intracavity tunable Mach-Zehnder interferometers that use voltage controlled phase modulators. In this paper we will discuss design considerations and advantages of such tunable lasers