The posting
Staff/Principal Thermal Engineer
About the Company Xscape Photonics is a cutting-edge technology company developing advanced photonic systems for high- performance computing and communication applications. Our work focuses on enabling next-generation optical interconnects through innovative integration of photonics, electronics, and packaging technologies. We are building highly efficient, scalable solutions where thermal management plays a critical role in performance, reliability, and product success. We are seeking a Staff or Principal Thermal Engineer to own thermal architecture, performance, and strategy for our photonic and electronic systems — from early concept through production. This is a high- ownership role: you will set the thermal design direction across programs, own module thermal performance against target temperature and crosstalk limits, lead the development of cooling solutions (TECs, TIMs, heat spreaders/heat sinks, air and liquid cooling), drive simulation and validation methodology, and own thermal-related failure analysis. You will represent thermal engineering in customer- and leadership-facing technical reviews, work closely with optical, mechanical, electrical, packaging, firmware, and reliability engineers, and mentor and guide other thermal engineers as the team scales.
Key Responsibilities Thermal Design & Analysis • Own thermal architecture and strategy for photonic modules and systems across multiple programs, from concept through production • Lead design and development of cooling solutions using: ◦ Thermoelectric coolers (TECs) ◦ Thermal interface materials (TIMs) ◦ Heat spreaders and heat sinks ◦ Air cooling and liquid cooling approaches • Perform thermal trade-off analysis across candidate designs, evaluating cost, power consumption, and mechanical and electrical complexity to guide architecture decisions • Lead critical cooling-technology, material, and supplier decisions (TECs, TIMs, cooling solutions), balancing product performance, cost structure, and long-term scalability • Set thermal simulation methodology and standards; drive CFD analysis strategy (temperature distribution, heat flow, thermal crosstalk) and review the work of other engineers • Define and own the thermal test and validation strategy, including instrumentation (thermocouples, IR imaging, DAQ/LabVIEW) and test-to-simulation correlation Thermal Failure Analysis • Own thermal-related failure analysis, working closely with the Lead FA Engineer on the overall FA process • Diagnose thermal-stack failure modes such as TIM pump-out and dry-out, solder void growth, bond-line degradation, TEC fatigue over thermal cycling, and warpage-driven loss of contact • Apply thermal FA diagnostic techniques — IR/lock-in thermography for hot-spot localization, thermal transient testing and structure-function analysis, and coordination of CT/acoustic microscopy for interface defect detection • Feed FA findings back into design margin, TIM/material selection, and thermal qualification criteria to prevent recurrence Cross-Functional Leadership • Own accountability for module thermal performance against targets — define the thermal budget, junction and case temperature limits, TEC/laser operating windows, and allowable thermal
crosstalk, and hold the design to them from prototype through production and across the product & operating life • Own thermal integrity of the system, including thermal runaway prevention, heat-path optimization, and definition and enforcement of worst-case operating margins and guard-bands across environmental and use-case variations • Represent thermal engineering in customer and executive/leadership reviews; present thermal compliance, risk, and trade-offs at program milestones • Partner with mechanical, PCB, and packaging engineering to integrate thermal requirements early in design • Support new product introduction (NPI) and transfer to manufacturing, including design for manufacturability and production ramp — working with contract manufacturers and assembly teams on TIM application, reflow, and thermal-stack assembly processes to ensure thermal performance holds in volume production • Mentor and provide technical guidance to junior and mid-level thermal engineers; may directly or indirectly lead a small thermal team as it scales • Own thermal risk assessment, design reviews, and technical documentation across programs Required Qualifications • Masters or PhD in Mechanical Engineering, Aerospace Engineering, or a related field, with a focus on heat transfer and fluid mechanics • 8+ years of thermal engineering experience for Staff, or 12+ years for Principal (PhD + 5+ years of industry experience may be considered equivalent to MS + 8+ years for Staff-level scope) • Demonstrated track record designing and delivering cooling solutions using TECs, TIMs, heat spreaders/heat sinks, and air and liquid cooling • Deep CFD simulation expertise (e.g., Ansys Icepak/Fluent, Ansys Mechanical, or equivalent) with a record of setting simulation strategy, not only executing models • Extensive hands-on thermal test and validation experience (IR imaging, thermocouples, DAQ systems) with demonstrated test-to-simulation correlation • Demonstrated root-cause problem solving and thermal failure analysis, including experience diagnosing thermal-stack failure modes and applying thermal diagnostic techniques (e.g., IR/lock- in thermography, thermal transient testing) • Experience owning thermal architecture at the system or program level, not solely at the component level • Strong teamwork and cross-functional collaboration skills, with the ability to work effectively alongside optical, mechanical, electrical, packaging, firmware, and reliability engineers • Excellent written and verbal communication skills, including the ability to present complex thermal analyses and trade-offs clearly to both technical and non-technical audiences • This is a full-time, on-site role based in Santa Clara, CA Preferred Skills • Experience in photonics, optical transceivers, or high-density electronics packaging • Experience with vapor chamber thermal design for high power-density, space-constrained applications • Experience presenting thermal compliance and risk directly to customers or executive leadership • Prior mentorship or direct/indirect leadership of other thermal engineers • Programming and data analysis skills (Python, MATLAB) for test automation and data processing • Experience with qualification/certification test campaigns and thermal reliability of materials and interfaces
What We Offer • Ownership of thermal strategy on advanced photonics systems at the ground floor of a fast- scaling startup • Collaborative and innovative work environment with direct access to leadership • Competitive salary, equity, and benefits • Career growth in a rapidly evolving technology space
