Doctorat in Leveraging the heterogeneous integration to develop Inp/Si based high-speed optoelectronic devices at wafer scale for optical communications

ABOUT TELECOM SUDPARIS

Telecom SudParis is a public graduate school for engineering, which has been recognized on the highest level in the domain of digital technology. The quality of its courses is founded on the scientific excellence of its faculty and on teaching techniques that emphasize project management, innovation and intercultural understanding. Telecom SudParis is part of the Institut Mines-Telecom, the number one group of engineering schools in France, under the supervision of the Minister for Industry. Telecom SudParis with Ecole Polytechnique, ENSTA Paris, ENSAE Paris and Telecom Paris are co-founders of the Institut Polytechnique de Paris, an institute of Science and Technology with an international vocation.

Its assets include: a personalized course, varied opportunities, the no.3 incubator in France, an ICT research center, an international campus shared with Institut Mines-Telecom Business School and over 60 student societies and clubs.

Context

In line with the technological revolution of our hyper connected society, there is a strong demand to improve the current data transmission systems to enable new communication channels which are faster, more secure and more energetically efficient. It is then necessary to develop new optical transceivers (transmitters and receivers) able to perform at high operation speeds (> 10 Tb/s) using a low cost technology. In this context, Silicon Photonics has recently raised as a promising and elegant solution able to fulfill all these requirements owing to the abundance on earth of its prime material, silicon (Si), and the maturity of the CMOS technology. Despite all these benefits, Si is an indirect band-gap material and therefore is known to have poor light emitting properties, hence providing a strong constrain when willing to develop Si-based light emitting sources. Nevertheless, other approaches are suitable, notably the heterogeneous integration of III-V semiconductor materials on Si platforms. In this regard, the III-V lab has demonstrated high performance III-V lasers, modulators and amplifiers heterogeneously integrated on silicon photonic platforms by using molecular bonding [1]. These devices have demonstrated good performance in terms of optical power, electro-optical bandwidth or high modulation extinction ratio, among others. Nevertheless, we need to continue scaling up the performance to attain the needs of modern optical links. A new generation of compact, low-cost and performant III-V-on-Si devices will be developed during this thesis to meet the expected performance.

In this thesis work, we will develop complex PICs that include: i) several laser sources operating at different wavelengths; ii) high-speed electro-optical modulators (electro-absorption and electro-refraction) and iii) an integrated optical interface for wavelength multiplexing-demultiplexing. In particular, the use of a wide spectral window in the telecom band will enable a more efficient.

Main objectives of the thesis

This thesis will focus on the development of high-speed transceivers in the O- and C-bands for the next generation optical communications. Devices will be developed in a heterogeneous integration platform composed by III-V heterostructures molecularly bonded onto an SOI wafer containing silicon photonic circuits. Concerning the application scenario, we will be targeting transceivers for high-speed passive optical networks (HS-PON). For that, laser wavelength values ranging from λ = 1270 nm up to λ = 1330 nm in steps of 20 nm for the O-band to demonstrate 4-channel CWDM transceivers or from λ = 1270 nm up to λ = 1410 nm for the O-band 8-channel CWDM will be investigated [2].

From a monolithic integration perspective of all these photonic components, it is essential to ensure that the parasitic reflections that may stem from multiple internal and external locations do not affect the stability of the device. A semiconductor laser when subjected to external optical feedback can present a large variety of dynamic behaviors (periodic and quasi-periodic oscillations, coherence collapse, low-frequency fluctuations or chaos). In particular, parasitic optical feedback usually causes instabilities that degrade the initial laser diode performances. For that, it is important to understand the behavior of III-V/Si devices when subjected to different types of optical feedback, and in particular the sensitivity to both coherent and incoherent optical feedback.

Important tasks/goals that will be pursued during the thesis include:

• Modelling and analytical analysis of the laser/electro-absorption modulator (EAM) dynamics and optoelectronic performances. The student will acquire an advanced knowledge on optics and fundamental physics that will allow him to analyse and predict the performance of lasers and EAMs.
• Simulations of optical devices. The student will learn to simulate optical devices as well as to extract the most important parameters that govern their functionality. He must have some knowledge on optical simulations.
• Advanced characterisation. The student will have access to the characterisation labs at the III-V lab and Telecom SudParis. He will perform static and RF characterisation of devices. Power versus current, electro-optical bandwidth, laser linewidth, saturation power, on-chip gain, side-mode suppression ratio or extinction ratio in modulators are some of the device parameters that will be analysed.
• - Study of the impact of optical feedback using different experimental setup (short to long feedback regime). The student will investigate both theoretically and experimentally the steady-state regime and the dynamical behavior of III-V/Si devices subject to optical feedback in the different feedback regimes. He will develop original methods in which controlled optical feedback is used for stabilizing a chaotic laser diode.

Organization plan of the thesis:

First period:

• Modeling and simulation of optical devices.
• Optoelectronic characterization of existing hybrid III-V/Si PIC.
• Development of experimental setups for the evaluation of optical feedback robustness.

Second period:

• Optoelectronic characterization of 2nd generation hybrid III-V/Si PIC.
• Modeling III-V PIC with optical feedback (based on Lang Kobayashi equations).
• Demonstration of a III-V/Si CWDM integrated transmitter.

Skills for the thesis:

• Good English level. The student will be fully immersed in an international environment, and so a good level of English (both spoken and written) is required to succeed.
• Team work. The interaction with the other members of the team and the other colleagues from the III-V lab and Telecom SudParis will be strongly beneficial during the thesis. Such interaction will help solving eventual challenges/problems during the thesis and will forge a solid professional relationship with research peers.
• Motivation. This last skill is at the core of any research activity and so it is a must to ensure the successful development of this thesis.

APPLICATION PROCEDURE

• Application deadline: November 8th, 2024
• Category and profession of the position: II - T, Doctoral
  
• To apply, please send us a CV, a cover letter and a summary of your doctoral thesis
• Location of the position : Palaiseau (France)
• The positions offered for recruitment are open to all with, on request, accommodations for candidates with disabilities
• Working conditions: Teleworking possible, restaurant and cafeteria on site, accessibility by public transport (with employer's participation) or close to main roads, staff association and sports association on campus
• Contact person: Kamel MERGHEM - 01 75 31 45 26