Position Title: Principal Firmware EngineerEmployment Type: Full-time, Existing vacancy
Location: San-Jose (On-Site)
Why You'll Love This RoleLumentum is seeking a
Principal Firmware Engineer to lead architecture, design, and development of embedded firmware for advanced optical and photonic systems. In this role, you will drive technical direction across firmware platforms, partner closely with hardware, systems, and manufacturing teams, and deliver robust, high-quality firmware that meets performance, reliability, and compliance requirements for high-volume products.
What You'll Be Doing- Own firmware architecture and technical roadmap for one or more embedded platforms supporting optical/laser/telecom or related high-reliability systems.
- Lead end-to-end firmware development: requirements 1 design 1 implementation 1 verification/validation 1 production release 1 sustaining.
- Develop firmware for MCU/MPU-based embedded systems (bare-metal and/or RTOS and/or embedded Linux), including board bring-up and low-level drivers.
- Define interfaces and protocols across firmware, hardware, FPGA, optics, and host software (e.g., I2C, SPI, UART, CAN, Ethernet; higher-layer protocols as applicable).
- Drive system reliability and quality: fault handling, diagnostics, telemetry, logging, upgrade mechanisms, and robust state-machine design.
- Lead design reviews, code reviews, and root-cause analysis for field issues; implement corrective and preventive actions.
- Collaborate cross-functionally with Systems, Hardware, Optical Engineering, Test, Reliability, Manufacturing, and Program Management to meet schedule and product goals.
What We're Looking ForEducation:
BS in Electrical Engineering, Computer Engineering, Computer Science, or related field (MS preferred), or equivalent experienceExperience:
Core Requirements:- 10+ years of professional embedded firmware development experience, including ownership of shipped products.
- Expert proficiency in C/C++ for embedded systems, source code control (GIT), Segger IDE, Python, data analysis tools (i.e. JMP, R), Windows & Linux.
- Deep experience with RTOS development (e.g., FreeRTOS) and Bare-metal firmware (interrupts, bootloaders, HAL/LL drivers).
- Strong skills in board bring-up, debugging, and lab tools (JTAG/SWD, logic analyzer, oscilloscope, optical power meter, optical wavemeter).
- Solid understanding of hardware/firmware integration and digital interfaces (I2C/SPI/UART, GPIO, ADC/DAC, timers, DMA).
- Proven ability to lead technical decisions, drive architecture, and deliver across multi-disciplinary teams.
- Hands-on experience with optical components/modules calibration and control/PIDs including optical power control/APC loops, bias/current tuning, heater/thermal control, TEC/thermal control, optical signal monitoring, fault management and trend-based telemetry
Preferred Qualifications- Direct experience developing firmware/software for optical transceiver modulesand subsystems including bring-up, feature development, and production support.
- Strong familiarity with module management and host interfaces, including CMIS (Common Management Interface Specification); experience implementing, debugging, and validating management behaviors (state machines, paging/banked memory, diagnostics, alarms, and telemetry).
- Experience with optical components (i.e. lasers, MZ/IQ modulators, et cetera) control (i.e. PIDs), performance monitoring, and fault management.
- Understanding of manufacturing test flows and firmware support/API for calibration, characterization, and end-of-line verification; experience building tooling or scripts (i.e., Python) to support these flows.
Leadership & Behavioral Competencies- Strong technical judgment; able to trade off schedule, risk, and quality with clarity.
- Excellent communication: can explain complex topics to non-firmware audiences.
- Ownership mindset and calm execution in ambiguous, high-urgency situations.
- Mentorship and influence: raises the bar for design quality and engineering culture.
Perks You'll Love- Flexible time off
- Health and wellness benefits (physical and mental)
- Tuition reimbursement and career growth support
- A workplace built for you: free gym, games room, prayer room
- Subsidized meals, free coffee/tea
- Employee stock options and incentive plans
- A collaborative, innovative, and inclusive culture
Join a Team That's Shaping the FutureAt Lumentum, we're more than just a workplace-we're a launchpad for creativity and innovation. We're committed to celebrating your unique talents and helping you grow. Our guiding principles-Innovate, Engage, Deliver, Excel, and Win-aren't just words; they're the heart of what we do.
Let's Build a Brighter Future Together! 
