Mjr Martijn Heck

Observation of Q-switching and mode-locking in two-section InAs/InP (100) quantum dot lasers around 1.55 µm

First observation of passive mode-locking in two-section quantum-dot lasers operating at wavelengths around 1.55 mum is reported. Pulse generation at 4.6 GHz from a 9 mm long device is verified by background-free autocorrelation, RF-spectra and real-time oscilloscope traces. The output pulses are stretched in time and heavily up-chirped with a value of 20 ps/nm, contrary to what is normally observed in passively mode-locked semiconductor lasers. The complete output spectrum is shown to be coherent over 10 nm. From a 7 mm long device Q-switching is observed over a large operating regime. The lasers have been realized using a fabrication technology that is compatible with further photonic integration. This makes the laser a promising candidate for e.g. a mode-comb generator in a complex photonic chip.

Design, Fabrication and Characterization of an InP-Based Tunable Integrated Optical Pulse Shaper

In this paper a tunable integrated semiconductor optical pulse shaper is presented. The device consists of a pair of arrayed waveguide gratings with an array of electrooptical phase modulators in between. It has been fabricated in InP-InGaAsP material for operation at wavelengths around 1.55 mum. Multimode inputs to the waveguide gratings are used to flatten their optical passband. We have used a new short-pulse characterization technique to fully characterize pulse shaping by the device, i.e., both the power and the phase profile. A fourfold decrease in pulse ringing was observed for the devices with flattened passbands. Moreover these devices showed a 25% increase in pulse peak power. The possibilities for using the device as a dispersion (pre-) compensator have been investigated. Pulse reconstruction could be obtained for dispersion values of up to 0.2 ps/nm. The fabrication technology of the pulse shaper is compatible with the fabrication of integrated mode-locked lasers, which makes further integration of complete arbitrary pulse generators possible.

Characterization of a 15 GHz integrated bulk InGaAsP passively modelocked ring laser at 1.53 μm

We report on an extensive characterization of a 15GHz integrated bulk InGaAsP passively modelocked ring laser at 1530 nm. The laser is modelocked for a wide range of amplifier currents and reverse bias voltages on the saturable absorber. We have measured a timing jitter of 7.1 ps (20 kHz - 80 MHz), which is low for an all-active device using bulk material and due to the ring configuration. Measured output pulses are highly chirped, a FWHM bandwidth is obtained of up to 4.5 nm. Such lasers with high bandwidth pulses and compatible with active-passive integration are of great interest for OCDMA applications.

Realization and modeling of a 27-GHz integrated passively mode-locked ring laser

We present a realization and the modeling of a 27-GHz integrated extended cavity ring laser that is passively mode-locked. The mode-locked ring laser is fabricated with active-passive integration. Experimental results show that internal reflections are the major factor affecting operation stability. Continuous-wave, self-pulsating, and in small windows of operation mode-locked regimes have been observed. Similar regimes have been observed in our bidirectional laser model. This model describes the semiconductor amplifier and the saturable absorber using rate equations. Our experimental and theoretical results are compared and discussed.

Simulation and design of integrated femtosecond passively mode-locked semiconductor ring lasers including integrated passive pulse shaping components

In this paper, a model is presented for the simulation of integrated passively mode-locked InP-InGaAsP ring laser systems that include active components such as an amplifier and saturable absorber, and passive components that can be frequency dispersive. These dispersive components can have a complex frequency dependence, such as arrayed waveguide gratings (AWGs). The model is a lumped-element model that is used as a design tool for developing integrated femtosecond pulse sources with internal dispersion control. Simulations based on an InP/InGaAsP amplifier and absorber show the possibility of laser designs that are able to generate pulses with pulse durations down to 300 fs in the 1550-nm wavelength range. The designs are based on femtosecond laser systems in bulk and fiber optics that are published in the literature. The femtosecond laser sources presented here can be realized using existing InP-InGaAsP active-passive integration technology.

Characterization of a Monolithic Concatenated SOA/SA Waveguide Device for Picosecond Pulse Amplification and Shaping

In this paper, a monolithic waveguide device, named IRIS, is presented. The device consists of an array of concatenated semiconductor optical amplifiers and saturable absorbers. We have fabricated the devices in InP-InGaAsP bulk gain material and we have experimentally investigated picosecond pulse transmission through these devices. Operated as an optical amplifier the IRIS devices show a decreased temporal pulse broadening and decreased amplified spontaneous emission noise generation as compared to a semiconductor optical amplifier of equivalent length. Used as a nonlinear element to increase the optical bandwidth of a picosecond pulse train, the spectra obtained with IRIS devices show an increased broadening and smoothness as compared to a semiconductor optical amplifier. We have set up a theoretical model to describe spectral and temporal pulse shaping by the IRIS device. Agreement between the simulations and the experiments is obtained.

Monolithic Multiband Nanosecond Programmable Wavelength Router

A compact scalable reconfigurable multiwavelength router is proposed and demonstrated using an electronically gated cyclic router. Simultaneous wavelength-multiplexed channel allocation is performed with power penalties of 0.2-0.8 dB. Nanosecond timescale reconfiguration is achieved within a 2-ns guard band using semiconductor optical amplifier gates.

Fast pulsed mode-locked lasers

InP integration technology and InAs/InP(100) quantum dot gain material are shown to be promising for realising fully integrated modelocked laser systems operating at 1.5 mum. Fast switching of output pulse parameters is possible with such systems.

Simulation of semiconductor mode-locked ring lasers with monolithically integrated passive pulse shaping elements

We present a model to simulate passive mode-locking in InP/InGaAsP monolithically integrated extended cavity ring lasers that include both active and passive components. For the development of integrated femtosecond semiconductor lasers we have extended the design for a PML ring laser with integrated pulse shaping components. Simulations of these designs show output pulse durations down to 300 fs.

Monolithic multiband wavelength router for fast reconfigurable data networking

A compact and highly scaleable reconfigurable wavelength router is proposed and demonstrated using an electronically-gated cyclic wavelength router. Power penalties for wavelength multiplexed 3×10Gb/s wavelength channels of order 0.2dB are achieved.