---
title: 'Senior Photonics Circuit Design Engineer at Lightmatter'
canonical: 'https://feeny.ai/job/senior-photonics-circuit-design-engineer-lightmatter-mountain-view-9w0g4dfzbxp2'
type: 'job'
last_seen: '2026-10-16'
---

# Senior Photonics Circuit Design Engineer at Lightmatter

- **Company:** Lightmatter
- **Location:** Mountain View, CA
- **Compensation:** $150k–$200k
- **Posted:** 2026-10-15
- **Last confirmed live:** 2026-10-16
- **Apply:** https://boards.greenhouse.io/lightmatter/jobs/5448430008?gh_jid=5448430008

## 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!

The Laser System Architecture & Engineering (LSAE) team is seeking a Photonics Circuit Design Engineer. The candidate will design and model the photonic and analog sub-circuits that make up Lightmatter's Guide™ laser products and Passage™ optical links. Examples include the laser source and wavelength-locking blocks, ring filter and modulator banks, mux/demux, optical power splitting and monitoring, and the photodetector-receiver front end.

You will own the bridge between device physics and sub-circuit behavior. You will build high-fidelity behavioral models that capture fabrication variability, dispersion and thermal effects. From them you will assemble sub-circuit models that accurately predict how each block performs. Systems architects will build their end-to-end product simulations on your models, so your models must be accurate, correlated to silicon, and ready to plug into larger simulations.

## Responsibilities

- Construct and maintain high-fidelity compact and behavioral representations for both active and passive silicon photonic elements, covering waveguides, couplers, MZIs, micro-rings, multiplexers, phase control elements, thermal tuners, modulators, detectors, and integrated III-V/SOA components.
- Incorporate process variations (waveguide geometry and etch biases), dispersion metrics, thermal-optical tuning characteristics, and non-linear properties directly into component modeling.
- Partner with device engineers to extract and calibrate parameter sets using optical solvers (FDTD, EME), foundry process design kits, and physical silicon data across various tapeouts to ensure high model correlation.
- Architect and deliver comprehensive sub-circuit simulations for Guide laser modules, encompassing optical sources, gain media, wavelength control loops, power distribution trees, monitors, and associated analog interfaces (TIAs, converters).
- Implement integrated sub-circuit models for Passage interconnect blocks, including modulated ring arrays, filter banks, thermal controls, drive circuits, DWDM MUX/DEMUX structures, and receiver front-ends.
- Refine sub-circuit topologies against core key performance indicators such as insertion loss, extinction ratio, signal isolation, tuning efficiency, operating bandwidth, and noise performance in collaboration with circuit and device teams.
- Execute corner, statistical Monte Carlo, and margin analyses to establish component tolerances, evaluate yield metrics, and inform experimental test vehicle vehicles and architecture reviews.
- Validate and iterate sub-circuit behavioral representations based on empirical silicon measurements across production cycles.

Required Qualifications

- Ph.D. in Electrical Engineering, Applied Physics, Photonics, or related discipline plus 2+ years of industry experience (or M.S. with 5+ years). Staff level targeting Ph.D. with 6+ years or M.S. with 10+ years.
- Deep background in silicon photonic physics and analog circuit fundamentals, with proven capability in generating behavioral component models for circuit-level co-simulation.
- Practical expertise using photonic modeling platforms (Lumerical, RSoft, Tidy3D) and analog IC suites (Cadence Virtuoso/Spectre).
- Strong Python software skills for modeling, data extraction, and maintainability of shared engineering codebases.
- Analytical mindset capable of addressing complex, unstructured technical issues through data-driven decisions.
- Methodical approach to engineering, with an emphasis on structured review processes and simulation automation.
- Clear written and verbal technical presentation capabilities.

## Preferred Qualifications

- Experience with microring modulators and filters, DWDM MUX/DEMUX, and thermal tuning.
- Laser and III-V photonics: DFB, external-cavity or comb sources, SOAs, wavelength lockers, and heterogeneous integration.
- Analog front-end experience with TIAs, modulator drivers, and heater drivers or DACs as they interface to photonic devices.
- Experience with foundry silicon photonics PDKs and process variation data (for example GlobalFoundries, TSMC, Tower, AIM or imec).
- Lab experience correlating models to measurement: OSA, tunable lasers, OVA/LCA, VNA, and wafer-level testing.
- Publications or patents in photonic circuit design or modeling.

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. $150,000—$200,000 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)

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