---
title: 'Mechanical Design Engineer at Lightmatter'
canonical: 'https://feeny.ai/job/mechanical-design-engineer-lightmatter-mountain-view-26vv2w50as1f'
type: 'job'
last_seen: '2026-10-16'
---

# Mechanical Design Engineer at Lightmatter

- **Company:** Lightmatter
- **Location:** Mountain View, CA
- **Compensation:** $135k–$212k
- **Posted:** 2026-05-13
- **Last confirmed live:** 2026-10-16
- **Apply:** https://boards.greenhouse.io/lightmatter/jobs/5208190008?gh_jid=5208190008

## Job description

Lightmatter is leading the revolution in AI data center infrastructure, enabling the next giant leaps in human progress. The company invented the world’s first 3D-stacked photonics engine, Passage™, capable of connecting thousands to millions of processors at the speed of light in extreme-scale data centers for the most advanced AI and HPC workloads.

Lightmatter raised $400 million in its Series D round, reaching a valuation of $4.4 billion. We will continue to accelerate the development of data center photonics and grow every department at Lightmatter!

If you're passionate about tackling complex challenges, making an impact, and being an expert in your craft, join our team of brilliant scientists, engineers, and accomplished industry leaders.

Lightmatter is (re)inventing the future of computing with light!

In this role, you will be working on leading-edge packaging technologies to enable AI architectures that set new industry standards for compute power, performance, and efficiency. As a member of the Packaging team, you will collaborate with several teams to identify key failure modes under product use conditions and run appropriate parametric design studies to influence product and package design upstream. You will be responsible for the package stack-up analysis, co-optimizing mechanical, optical and thermal aspects that influence package form factors, and driving socket/enabling mechanisms. You will utilize Geometric Dimensioning and Tolerancing (GD&T) to propose solutions that finalize the design. Your work will result in advanced package designs that meet power dissipation, assembly, optical, and reliability requirements, while delivering a system level solution for leading edge products in the data centers and high-end compute segment.

Responsibilities:

- Create CAD models of package stack-up and associated components.
- Perform mechanical design analysis to identify and implement solutions that improve package mechanical integrity.
- Execute tolerance stack-up analyses and create GD&T drawings for advanced packages — including optically aligned assemblies where micron-level precision defines product performance
- Apply manufacturing expertise to influence design choices, perform FMEAs, and evaluate the cost implications of process and design decisions.
- Collaborate with package and systems teams to ensure packaging solutions comply with system boundary conditions.

Requirements:

- BS or MS in Mechanical Engineering or a related field.
- Minimum of 3 years of mechanical design experience in semiconductor packaging, optoelectronics, or photonics modules.
- Proficiency in CAD tools such as Solidworks or Creo, with a focus on mechanical design best practices.
- Expertise in Geometric Dimensioning and Tolerancing (GD&T) and tolerance stack-up analysis.
- Manage prototype builds with external vendors, validating the designs, and ensuring the scalability to high volume manufacturability.
- Working knowledge of semiconductor packaging technologies, including the mechanical and thermal trade-offs of 3D, 2.5D, and FCBGA architectures.

## Preferred Qualifications

- Knowledge of ASME Y14.5 standards.
- Ability to drive results independently and with minimal supervision.
- Working knowledge of FEA tools (ANSYS, Abaqus, or similar) for structural and thermal analysis.
- Fiber array unit (FAU) attach, optical connector, or photonic alignment experience.
- Experience with liquid cooling or advanced thermal architectures for AI/HPC systems.
- Exposure to high-volume manufacturing and OSAT engagement in Asia.
- Strong cross-functional communication skills and a bias toward fast, data-driven iteration.

We offer competitive compensation. The base salary range for this role determined based on location, experience, educational background, and market data.

Salary Range: total compensation goes beyond base salary, it also includes a new hire equity grant, annual performance-based equity, and other rewards that recognize your impact and contribution. $135,000—$212,000 USD

## Benefits

- Comprehensive Health Care Plan (Medical, Dental & Vision)
- Retirement Savings Matching Program
- Life Insurance (Basic, Voluntary & AD&D)
- Generous Time Off (Vacation, Sick & Public Holidays)
- Paid Family Leave
- Short Term & Long Term Disability
- Training & Development
- Commuter Benefits
- Flexible, hybrid workplace model
- Equity grants (applicable to full-time employees)

Benefits eligibility may vary depending on your employment status and location. Lightmatter recruits, employs, trains, compensates, and promotes regardless of race, religion, color, national origin, sex, disability, age, veteran status, and other protected status as required by applicable law.

Export Control

Candidates should have capacity to comply with the federally mandated requirements of U.S. export control laws.

## About Lightmatter

## Company Overview
- **One-liner**: Lightmatter builds photonic interconnects and computing infrastructure to eliminate bandwidth bottlenecks in AI and high-performance computing, enabling the next era of AI scaling.
- **Entity Type**: Private (Series D, $850M total funding)
- **Headquarters**: Mountain View, California, USA
- **Founded**: 2017
- **Founders**: Nicholas Harris, PhD (CEO), Darius Bunandar, PhD (Head of Machine Learning), and a third co-founder (Chief Scientist)

## Core Business
- **Primary industry**: Silicon Photonics / AI Infrastructure / Semiconductor
- **Target customers**: Hyperscale data center operators, AI labs (training frontier models), cloud service providers, and enterprise AI teams
- **Mission or purpose**: To make computers keep getting better by using light instead of electricity for data movement, solving the fundamental bandwidth bottleneck that limits AI scaling.

## Products & Services
- **Passage™ Platform**: A family of 3D-stacked silicon photonics interconnects (NPO, OBO, 2D/3D CPO, 3D interposers) that provide "Edgeless I/O"—unlimited bandwidth scaling for AI supercomputers. Key variants include:
  - **Passage M1000 EVK**: Rack-level 3D photonic interposer delivering 114 Tbps across a 4,000 mm² footprint.
  - **Passage L200**: Designed for frontier-scale training, supporting 32–64 Tbps aggregate bandwidth via co-packaged optics (112G PAM4).
  - **Passage L20**: Accelerates optics integration with 12.8 Tbps aggregate bandwidth and 4x pluggable density.
  - **Passage EVK100**: High-bandwidth bidirectional link at 3.2 Tbps per fiber, 1.9 pJ/bit.
  - **Passage EVK50**: 16-wavelength bidirectional link at 800 Gbps per fiber, 2.6 pJ/bit.
- **Guide® Light Engines**: Very Large Scale Photonics technology—a universal light source (hundreds of lasers and photonics components on a single chip) designed to power co-packaged optics across the entire photonics industry.

## Market Standing
- **Valuation**: $4.4 billion (as of October 2024)
- **Key Metric**: $850M total funding raised
- **Notable Investors/Partners**: TSMC, GlobalFoundries, Tower Semiconductor (manufacturing partners); Amkor, ASE (packaging partners); NVIDIA (joined NVLink Fusion ecosystem); standards bodies including Ultra Ethernet, UALink, JEDEC, OIF, IEEE, OCP, and the Advanced Photonics Coalition.
- **Growth Signals**: First-mover in category-defining photonic interconnects; multiple generations of production-ready technology (not vaporware); reference platforms in customer hands; 100,000+ GPU cluster capability; world-first 16-wavelength bidirectional optical DWDM link on standard single-mode fiber (8x leap in bandwidth density); partnerships with top foundries ensure high-volume manufacturing.

## Competitive Advantages
- **Edgeless I/O architecture**: Eliminates the physical chip-perimeter constraint that limits electrical interconnects, enabling bandwidth to scale without bound.
- **Fundamentally better physics**: Photons travel without resistive loss, cross paths without interference, and carry multiple signals on a single fiber—far more efficient than electrons.
- **Deep vertical integration**: From photonic chip design to light engines (Guide) to complete interconnect platforms (Passage), with proprietary 3D stacking technology.
- **Decade-scale roadmap**: Continued bandwidth scaling (114 Tbps today, 1+ Pbps tomorrow) with production-ready silicon validated at scale.
- **Ecosystem lock-in**: Standards body leadership and partnerships with NVIDIA, TSMC, and hyperscalers create high switching costs.

## Strategic Focus
- **Scale AI infrastructure**: Enable 100,000+ GPU clusters for trillion-parameter models, solving the interconnect bottleneck that currently strands hundreds of millions in compute capacity.
- **Productize photonics**: Move from reference platforms to volume production across Passage and Guide families, targeting both training and inference workloads.
- **Expand ecosystem**: Deepen partnerships with hyperscalers, AI labs, and chipmakers (e.g., NVIDIA NVLink Fusion) to make photonic interconnects the default for next-gen data centers.
- **Hire across all functions**: Actively growing engineering, research, sales, and operations teams to scale the company.

## Why Work Here
- **Mission-driven impact**: Work at the intersection of photonics, AI, and semiconductor engineering to solve the most critical bottleneck in AI—data movement. Your work directly enables frontier models and trillion-parameter training.
- **World-class team**: Colleagues from MIT, Caltech, Stanford, and UC Berkeley; published in Nature, Science, ISSCC, ISCA; 100+ patents; team members contributed to black hole simulation software for the Academy Award-winning movie *Interstellar*.
- **Cutting-edge technology**: Not research, not vaporware—multiple generations of production-ready photonic chips in customer hands, with a decade-scale roadmap.
- **Locations**: Mountain View, CA (HQ); Boston, MA; Hsinchu, Taiwan; Toronto, Canada.
- **Benefits**: 401(k), generous vacation policy and holidays, commuter benefits, happy hours, and a strong learning culture (peer-to-peer knowledge sharing across electronics, photonics, machine learning, and more).
- **Culture**: "We are one Lightmatter"—collaborative, cross-disciplinary, and focused on solving hard problems at scale.

## Sources
1. [lightmatter.co/about](https://lightmatter.co/about/)
2. [lightmatter.co](https://lightmatter.co/)
3. [lightmatter.co/people/careers](https://lightmatter.co/people/careers/)
4. [lightmatter.co/people](https://lightmatter.co/people/)
5. [linkedin.com/company/lightmatter](https://www.linkedin.com/company/lightmatter)

## Other roles at Lightmatter

- [New Product Introduction (NPI) Engineer](https://feeny.ai/job/new-product-introduction-npi-engineer-lightmatter-mountain-view-je7te558y220) — Mountain View, CA
- [Senior Photonics Circuit Design Engineer](https://feeny.ai/job/senior-photonics-circuit-design-engineer-lightmatter-mountain-view-9w0g4dfzbxp2) — Mountain View, CA
- [Photonic Architect,  Temp](https://feeny.ai/job/photonic-architect-temp-lightmatter-toronto-6psysb195ped) — Toronto, Canada
- [Staff Photonics Design & PDK Modeling Engineer](https://feeny.ai/job/staff-photonics-design-pdk-modeling-engineer-lightmatter-boston-h60aef4xtyr4) — Boston, MA / Mountain View, CA / Toronto, Canada
- [Sr SDET– Firmware Automation](https://feeny.ai/job/sr-sdet-firmware-automation-lightmatter-toronto-9ap6p3s48g3p) — Toronto, Canada
- [Principal Product Manager, Photonics](https://feeny.ai/job/principal-product-manager-photonics-lightmatter-mountain-view-z3k6bf5y33fy) — Mountain View, CA
- [Photonics Architect](https://feeny.ai/job/photonics-architect-lightmatter-boston-nfpcb2sf5mhp) — Boston, MA / Mountain View, CA
- [Sr. Staff Product Manager (Photonics)](https://feeny.ai/job/sr-staff-product-manager-photonics-lightmatter-boston-ndfkcw7n0sew) — Boston, MA / Mountain View, CA
- [Sr SDET– Firmware Automation](https://feeny.ai/job/sr-sdet-firmware-automation-lightmatter-boston-5amw6cysx86a) — Boston, MA / Mountain View, CA
- [Electro-Optic Link Hardware Engineer](https://feeny.ai/job/electro-optic-link-hardware-engineer-lightmatter-mountain-view-cdm8nk3v6xa6) — Mountain View, CA