The ever-increasing demands in traffic fueled by bandwidth hungry applications are pushing data centers to their limits challenging the capacity and scalability of currently established transceiver and switching technologies in data center interconnection (DCI) networks. Coherent optics emerged as a promising solution for inter-DCIs offering unprecedented capacities closer to data centers and relaxing the power budget restrictions of the link. QAMeleon, an EU funded R and D project, is developing a new generation of faster and greener sliceable bandwidth-variable electro-optical transceivers and WSS switches able to handle up to 128 Gbaud optical signals carrying flexible M-QAM constellations and novel modulation techniques. A summary of the progress on the QAMeleon transponder and Reconfigurable Optical Add/Drop Multiplexer (ROADM) concepts is presented in this paper.
We report on a record broad 3-dB bandwidth of 14 nm (~1.8 THz around 1532 nm) optical frequency comb generated
from a passively mode-locked quantum-well (QW) laser in the form of photonic integrated circuits through an InP
generic photonic integration technology platform. This 21.5-GHz colliding-pulse mode-locked laser cavity is defined by
two on-chip reflectors incorporating intracavity phase modulators followed by an out-of-cavity SOA as booster. Under
certain operating conditions, an ultra-wide spectral bandwidth is achieved along with an autocorrelation trace confirming
the mode locking nature exhibiting a pulse width of 0.35 ps. The beat note RF spectrum has a linewidth of sub-MHz and
35-dB SNR.
In this paper, a theoretical investigation of the coupling phenomena of two laterally coupled diode lasers is
presented. The analysis is centered in a new dynamic modeling of laterally coupled diode lasers where the modulation
response shows additional resonance that is beyond the normal relaxation oscillation frequency. This additional
resonance is attributed to the coupling effect between the two coupled diode lasers. We present results obtained with this
new model and we compare them with previous experimental results in order to demonstrate the good agreement
between them.
The analysis of the locking, unlocking and non linear dynamics observed in lateral couple diode lasers (LCDL) is a key
issue on the study and understanding of these devices. In this work an analysis of the different nonlinear regimes
observed in these devices is made. By the observation of both the RIN spectrum and the high resolution Fabry Perot
optical spectrum, a clear identification of the different nonlinear regimes is made. From these measurements a mapping
of the nonlinear regimes is presented.
The analysis of the non linear dynamics observed in lateral couple diode lasers (LCDL) is a key issue on the study and
understanding of these devices. In this work an analysis of the different nonlinear regimes observed in devices with
different lateral distances is made. By the observation of both the RIN spectrum and the filtered optical spectrum, a
clear identification of the different nonlinear regimes observed in these devices is made, as well as an identification of
the main variables responsible for the appearance of these nonlinear regimes.
The analysis of the dynamics of lateral couple diode lasers is a key issue on the study and understanding of these
devices. In this work a detailed study of the different nonlinear regimes observed in these devices is made. By the
observation of both the RIN spectrum and the filtered optical spectrum, a clear identification of the different regimes
dependence with the relative bias was achieved.
The analysis of the RIN spectrum of the LCDL devices allows important information on the nonlinear behaviour of
Laterally Coupled Diode Lasers (LCDL). Under certain bias conditions, the second resonance frequency characteristic
of the LCDL devices is at double the relaxation oscillation frequency and, for the first time, a period doubling is
observed. This effect is similar to a single diode laser when is current modulated at the double of the relaxation
oscillation frequency. So, in this paper a comparative study between period doubling evolution obtained in LCDL
device versus the single laser diode is made.
The study of the coupling phenomena and of the operation regions in laterally coupled diode lasers is a major key parameter for the understanding and development of these devices as a solution for the new optical communications systems. To understand the behaviour of these devices a complete study of their dynamics must be performed. In order to do so, in this paper a study of both the noise spectrum and frequency response is made. The aim of this study is to compare the performance of these devices as a single ridge laser and as a twin stripe operation.
The study of noise spectrum, in particular of the RIN, in semiconductor diodes lasers is a powerful tool to determine the proper frequencies and the operation regimes of the device. Following this a study of the RIN is of major importance to characterize the laterally coupled diode lasers. In this work a study of the noise spectrum dependence with the lateral separation between waveguides as well as its dependence with relative bias current applied is made. These results combined and compared with spectrally resolved near and far field allows the definition of which are the operating regimes of the device.
The coupling phenomena dependence with the lateral separation between the laser stripes in laterally coupled diode lasers is of major importance for the design of these devices as a solution to overcome the intrinsic bandwidth limitation of semiconductor lasers. In this work an experimental study of the coupling dependence with the separation between laser stripes is presented. For that purpose a comparison of the spectrally resolved near and far fields and of the frequency responses obtained with the laterally coupled diode lasers for devices with different separation between the ridges is made.
In this work a study of the dependence of the coupling in laterally coupled diode lasers (LCDL) with the relative bias conditions is presented. The study is made by the analysis of the spectrally resolved near and far field optical spectrum combined with the frequency responses of these devices at different bias conditions. By the analysis of these measurements it was observed that three different operation regions appear, and are identified by the spectral phase relation between the fields emitted by each laser stripe.
The objective of this work is to analyse the dependence of the frequency response of Laterally Coupled Diode Lasers (LCDL) focusing on the separation between the laser ridges. A detailed study of the integrated optical spectra and frequency response is presented for LCDLs with 300 μm cavity length and separation between the ridges of 2, 4, 6, 8 and 10 μm. This study is of major importance as it defines the range of frequency locking for each ridge spacing and
also its dependence on the bias conditions applied.
The effects of inter-ridge coupling on both the static and high frequency properties of twin stripe laterally coupled lasers emitting at a wavelength of 1.3 micrometers are investigated. It is found that when both ridges are lasing, the emission spectrum is multi longitudinal mode, with each peak being single valued close to threshold, or split in two at higher biases. Spectrally resolved near and far field measurements are made which clearly distinguish that the system lases predominantly in the out-of-phase mode close to threshold, whereas it lases in both in-phase and out-of-phase modes at higher biases. The out-of-phase mode is found to emit at higher frequencies than the in-phase mode.
We report on the combined theoretical and experimental observation of an increase of the small signal modulation response of a Laterally Coupled Diode Laser (LCDL) system beyond its relaxation oscillation frequency. The increase is achieved by means of lateral coupling. Theoretical approaches are presented to explain the experimental observations obtained with these LCDL devices. Our results shed light on the principle of diode laser coupling an open up new perspectives for LCDL for high-speed optical communications.
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