PhD in Entanglement Routing in Quantum Optical Fiber Networks

PhD in Entanglement Routing in Quantum Optical Fiber Networks

Quick Decision

How can entangled photons be routed through a multi-node fibre network that also carries ordinary telecom traffic? The doctoral researcher will develop an architecture and protocols, build a testbed, and compare theoretical and simulated performance with optical experiments. The work sits in TU/e’s Smart Optical Networks Lab (SONL), within Electro-Optical Communication (ECO), with full funding from KPN. Scalability, interoperability, reliability and manageability are part of the research context, alongside quantum-state quality. Preparation therefore needs both programming and a firm physical-layer foundation.

The TU/e recruitment record lists reference 2026/639, one full-time post, publication on 14 October 2026 and a 14 November 2026 last application date. A second notice gives 15 November, but its encoded timestamp points to 14 November. The exact closing time and present vacancy status are unconfirmed. The employer says applications are screened on receipt and the post may close once filled; check current availability before applying. The position advertises four years, a nine-month assessment and €3,204–€4,051 gross monthly base pay. See Official TU/e vacancy 2026/639.

There is a positive general route for domestic Chinese applicants through the non-EU researcher/PhD residence framework and university degree assessment. Individual selection, C1 English evidence, any knowledge-security screening and immigration approval remain separate conditions. Before investing in a proposal, confirm the portal materials and the physical network assumptions that will define the doctoral work.

Research Problem and Doctoral Work

A classical router can work with copied data, electronic buffers and retransmission. Arbitrary unknown quantum states cannot simply be copied or amplified, and their measurement can disturb them. Loss, noise and decoherence therefore interact with control decisions. A route that is short in fibre distance may still perform poorly if switches lose too many photons, the classical channels add noise, or coordination consumes the useful entanglement lifetime. This is the scientific motivation for evaluating physical quality and protocol behaviour together.

The doctoral researcher will set up a multi-node optical-fibre testbed with entanglement generation and detection, frequency conversion and nodes linked by optical switches. The research covers routing quantum/classical packets and measuring coexistence effects such as noise and crosstalk, using theory, simulation and experiments together. It does not specify the photon encoding, number of nodes, fibre type, distances, source/detector specifications, memory technology or a repeater architecture. In particular, routing photons through a switch and establishing remote entanglement through swapping are different operations. The advertised scope does not establish that quantum memories, repeaters or a working teleportation service already exist.

The 2025 NIST-authored survey distinguishes routing policies and the assumptions they need: generation probabilities, entanglement fidelity, classical signalling, swapping and memory lifetimes. It supports a useful interview question: which of those resources will this testbed actually provide? A credible comparison must state that answer before choosing an algorithm. The survey does not make a shortest-path algorithm universally optimal. See Entanglement-routing survey and protocol assumptions.

Possible research angles, rather than assigned deliverables, include a routing objective that trades useful pair rate against a fidelity target; scheduling classical control without excessive waiting; and choosing switching/filtering or conversion settings under measured coexistence noise. A preparation plan could connect a physical impairment model to network simulation and then test selected cases on hardware. Suitable outputs might be a reproducible protocol implementation, calibrated model and experimental operating envelope. The employer does not promise a specified publication count or prescribe one simulator.

Measurements should distinguish coincidence counts, entanglement quality and, where a QKD protocol is actually implemented, secret-key rate; these quantities are not interchangeable. Suggested comparisons include quantum-only operation, classical traffic at controlled launch powers, alternative paths and a fixed-routing baseline. Record loss, filtering, detector background, timing windows and drift, rather than attributing every degradation to the routing algorithm. Frequency conversion also needs to preserve the relevant quantum correlations with an acceptable noise budget; its presence on a block diagram is not validation.

External work shows both momentum and limits. A 2025 Bristol/Southampton-led preprint reports entanglement/classical coexistence in an 11.5 km hollow-core-fibre four-user setup. Its system and results sections explain the central pair source, q-ROADM distribution and quantum/classical measurements. That supplies a concrete comparison, not a TU/e result or a claim that ordinary deployed silica fibre gives the same performance. Nor does a four-user distribution experiment establish a universal repeater network. See External hollow-core coexistence experiment.

School, Programme and Field Context

The official vacancy and institutional records place this post in SONL, ECO, Department of Electrical Engineering, Eindhoven University of Technology. SONL works across photonic integrated switches, network architecture, software control and FPGA/SDN implementations, including secure quantum-optical routing. This combination is relevant to linking a photonic experiment to a network protocol. It does not identify the equipment reserved for the new PhD. See SONL research and departmental affiliation.

TU/e is the employing university and intended doctoral institution. KPN funds and contributes industrial expertise; no KPN employment contract, joint degree or second degree is advertised. This is a research PhD rather than an EngD traineeship. The cited national doctoral framework describes recognised master's preparation, independent research, a thesis and defence. The references here do not set out current TU/e-specific admission and degree rules, so formal registration, authorised promotor, course credits, thesis conditions and any charges remain to be confirmed. See National doctoral framework.

For institutional comparison, ShanghaiRanking places TU/e in ARWU 2026 overall band 301–400; its profile gives GRAS 2026 Automation & Control rank 22 and Energy Science & Engineering band 76–100. Those are surrounding engineering signals, not a subject ranking of quantum communications. They cannot establish this laboratory's entanglement achievements or mentoring quality. The ranking references cited here do not provide a quantum-network-specific comparison. See ShanghaiRanking TU/e profile.

The regional setting includes other communication research. A Quantum Delta NL announcement describes the QuCT NL testbed launched in Eindhoven in August 2025, with QKD/PQC, control and verification capabilities. TU/e's QCINed record describes complementary QKD deployments but marks that 2023–2025 project as finished. Neither source automatically grants this PhD access, makes the project part of KPN's award, or shows entanglement routing already operational. QKD, post-quantum cryptography and a general entanglement network should remain distinct. See QuCT NL launch description and TU/e QCINed record.

Training also has employment conditions. The published English CLA 2025–2026 requires an individual training/guidance plan within three months, identifying mentor/promotor, skills and minimum guidance time. UNL confirms a new 2026–2027 agreement, while the available consolidated English link remains the previous version; ask HR for the operative implementation. The vacancy specifically requires teaching across at least 10% of four-year employment, capped at 15% in any one year, including mentoring BSc/MSc students. See Published CLA training provisions and Current UNL agreement status.

Supervisor and Lab Assessment

Prof Nicola Calabretta is the hiring manager and scientific contact, N.Calabretta@tue.nl; HR enquiries go to HRServices@tue.nl. His official profile identifies a full professor in ECO/SONL working on optical-network control, optical processing, integrated switches and FPGA scheduling. These are relevant strengths. The formal promotor appointment, daily quantum-optics mentor and KPN supervision split are not specified. See Calabretta official profile.

Three team papers provide evidence of capability, with different reading depth and a clear technical boundary:

• Xue and Calabretta, Nature Communications, 2022: The paper reports a four-ToR classical prototype combining FPGA label control, clock distribution and a 4×4 SOA switch, with 43.4 ns switching/control and 3.1 ns recovery; larger network scaling is simulated. The transferable skill is hardware/protocol co-design; its RAM buffering, copied packets and ACK/NACK retransmission cannot be applied wholesale to unknown quantum states. Nanosecond classical switching/control paper.
• Freire Santana, Mefleh and Calabretta, JOCN, 2025: the official complete abstract describes time-slotted reservation and a ring prototype with sub-microsecond reconfiguration. Publisher affiliations include KPN. This supports a history of operational network/control collaboration, but it is a classical optical experiment. The evidence presented here is limited to the official complete abstract; robustness details beyond it cannot be assessed. Metro-access FPGA-control paper.
• Rasoulzadeh Zali and colleagues, Optics Express, 2026: the author abstract indexed in PubMed describes a compact InP 8×8 SOA switch with measured polarization dependence and classical transmission tests. It indicates photonic integration expertise, not quantum-state preservation: optical gain and classical BER do not establish entanglement fidelity or a single-photon noise budget. The discussion here is limited to the author abstract indexed in PubMed. Integrated 8×8 optical-switch paper.

These publications make the control/integration side credible. The cited team papers do not demonstrate end-to-end entanglement routing by this group. Ask how quantum-state generation, conversion and detection expertise will be supplied, whether the relevant hardware is working, and how the project proceeds if quantum integration takes longer than planned. The strongest evidence of the new opportunity's funding is the official vacancy itself, which explicitly names KPN; a sponsor announcement does not replace the eventual employment contract.

Funding, Application and Living Cost

The official terms are a four-year full-time temporary post with an assessment after nine months. The supplied notice states 38 hours per week. Scale P gives €3,204–€4,051 gross base salary per month, plus 8% holiday allowance and 8.3% year-end bonus on annual gross base salary. For twelve months at an unchanged endpoint, that totals approximately €44,715–€56,536 gross annually. This arithmetic does not imply the maximum salary at entry or an individual net-pay quotation.

The final 2026–2027 pay agreement specifies a 3.1% increase followed by €50 from July 2026, consistent with the advertised P endpoints when applied to the previous table. A €1,534 one-off payment is tied to employment on 1 July 2026 and should not be assumed for a future recruit. Confirm starting step, progression and future applicable salary tables. See Final 2026–2027 pay agreement.

Benefits include 29 leave days on a 38-hour week, or 41 under the scheme involving two extra weekly hours, and ABP pension-premium sharing of 70% employer/30% employee. The latter is a premium split, not a 30% gross-salary deduction. The vacancy also describes parental-leave arrangements, campus childcare, discounted sports access, free 24/7 OpenUp for employee/family, commuting/home-working/internet allowances, immigration assistance and a conditional expat tax scheme. Ask what is charged or eligible and whether equipment, conferences, thesis costs and an overrun are funded. “Fully funded by KPN” does not answer all those cost categories.

For housing, Holland Expat Center South lists furnished Eindhoven studios around €1,100–€1,400 monthly, and one-bedroom apartments €1,400–€1,750, excluding utilities. Availability and the observation date behind these indicative ranges are not guaranteed. Add service charges, municipal taxes, deposit and temporary accommodation to relocation planning; the vacancy promises no housing allocation. See Eindhoven rental guide.

The national student reference of €1,000–€1,500 per month uses a 2024 breakdown and is a broad comparator, not a sufficient budget for every employee renting alone. Dutch basic health-insurance obligations also apply, with individual premiums and possible out-of-pocket costs. Net salary depends on tax, pension and personal circumstances. See National student living-cost reference and Government health-insurance guidance.

The Tax Administration exempts qualifying scientific research at designated institutions from the generic expat income test; other eligibility conditions and a valid ruling still apply. The employer need not grant the maximum tax-free percentage. Obtain HR calculations with and without the applicable scheme rather than assuming a fixed take-home amount. See Expat Scheme eligibility conditions.

The application must include a motivation/qualifications cover letter and a CV with publication list and three referees' contact details; notify them because they may be approached at any stage. The employer also asks for bachelor's/master's theses and scientific papers, if any. Submit through the online application route: email or postal applications are not processed. Confirm how unavailable/in-progress theses should be handled, file limits and the exact closing clock. The post has no published start date.

Applicant Fit and Preparation

Required: a master's or equivalent in applied physics, physics, electrical engineering or related subject; a solid background in fibre-optic communication, quantum optics and networks; programming such as Python; research and interdisciplinary/industrial collaboration ability; willingness to teach and coach; spoken and written English at C1. No specific IELTS/TOEFL conversion is advertised, so do not invent a test threshold.

Preferred: previous quantum optical communication/network experimental setup and electronics/FPGA background. Existing FPGA mastery and a full quantum-testbed portfolio are not listed as compulsory. However, a pure graph-algorithm or classical networking profile needs evidence of optical/quantum preparation; conversely, an optics-only profile needs programming and network reasoning. These are non-personal research-fit observations, not predictions of admission.

Suggested preparation: document a small optical or simulation project with assumptions, timing/control logic, measured or simulated impairments and uncertainty. Explain what a fidelity target means and how it differs from throughput. A simple baseline with honest resource assumptions is more useful than an elaborate idealised quantum-network optimiser. A proposal is not listed as a compulsory document; use such work as relevant evidence rather than adding an invented application condition.

Domestic Chinese applicants are eligible in principle under the general pathway: IND explicitly provides for non-EU PhD researchers, the employer assesses doctoral-entry degree suitability, and Technische Universiteit Eindhoven is a listed research sponsor. These are affirmative institutional routes, not inference from silence about nationality. They do not waive degree assessment, C1 evidence, recruitment, immigration or role-specific screening. See IND non-EU researcher/PhD route and IND research sponsor register.

The vacancy explicitly permits pre-employment knowledge-security screening. Its linked 2022 national guidelines treat research content and collaboration context as risk factors and mention quantum technology. That historical document is not a complete statement of 2026 law and does not establish either a blanket Chinese-nationality exclusion or individual clearance. Ask HR about the actual assessment and permitted access for this position before accepting. See Employer-linked knowledge-security guidelines.

Career and Field Context

The realistic career value is portable experience in optical experiments, photon-compatible control, Python analysis, FPGA interfaces and telecom validation. KPN's 2025 annual report confirms continued preparation in quantum/photonics with universities, while testbed sources show a research/development ecosystem. They give no graduate hiring volume, salary or guaranteed KPN position. An applicant comparing opportunities should therefore ask what independent technical responsibility and publishable work the collaboration will provide. See KPN annual-report innovation context.

Next Actions and Questions to Verify

Before applying: use official reference 2026/639 and the 14 November date; confirm closing clock, file limits, missing thesis handling, three-referee details and acceptable C1 evidence. Ask how a foreign master's will be assessed and whether any screening steps affect the application timeline.

At interview: distinguish switched photon paths from entanglement swapping; identify encoding, source/detectors, conversion and memory/repeater assumptions. Ask which hardware is already operating, what classical traffic and fibre will be tested, which fidelity/rate/noise baselines define success, and who provides daily quantum-optics and industrial supervision. Confirm the nine-month criteria and teaching schedule.

Before accepting: obtain the written employment/salary/registration arrangements, KPN IP and publication-review rules, equipment and travel budgets, any field-access restrictions, delayed-experiment contingency and immigration/housing plan. The next useful step is to assemble the stated documents and connect one concrete piece of prior work to a testable quantum/telecom coexistence question.

Evidence and Sources

The recruitment materials cited here are dated 17 October 2026. One record lists 14 November, while a second notice lists 15 November and its encoded timestamp points to 14 November; the exact closing time and current vacancy status remain unconfirmed. Evidence depth differs across the team papers: the 2022 paper supports discussion of its full results, methods and discussion, while the 2025 and 2026 papers support only abstract-level conclusions. The external hollow-core preprint and the NIST survey provide context, not evidence of a completed TU/e quantum network.

Vacancy, team and technical research

• TU/e official recruitment portal, reference 2026/639
• Nicola Calabretta official profile
• SONL official research scope and affiliation
• Xue and Calabretta (2022): nanosecond optical switching and control
• Freire Santana, Mefleh and Calabretta (2025): metro-access FPGA control
• Rasoulzadeh Zali et al. (2026): low-polarization 8×8 optical switch
• Abane et al. (2025): comprehensive entanglement-routing survey
• Clark et al. (2025): hollow-core entanglement and classical coexistence
• Quantum Delta NL (2025): QuCT NL launch
• TU/e QCINed QKD-Testbed project record

Training, salary and eligibility

• National Knowledge Security Guidelines (2022), linked by the employer
• UNL current collective agreement overview
• Final2026–2027 Dutch Universities pay agreement
• Published English CLA2025–26: scaleP/training framework
• IND affirmative non-EU researcher/PhD permit route
• IND researcher sponsor register
• Nuffic Study in NL doctoral research overview
• ShanghaiRanking2026 TU/e overall and relevant subjects
• Tax Administration Expat Scheme conditions

Industry and living costs

• KPN 2025 annual report: network innovation
• Holland Expat Center South Eindhoven private rent guide
• Dutch government health insurance obligations
• Study in NL: national living-cost reference