C

Coherent

Global laser technologies and systems supplier

Principal Silicon Photonics Wafer Test Engineer

Full-Time
No salary listed
Senior
Bachelor's
Fremont, CA, USA
HybridHybrid position with occasional off-site meetings or travel.
Hardware EngineeringHardware Validation & Testing

About the job

Requirements
  • A bachelor's degree or higher in Electrical Engineering, Optical Engineering, Physics, or a related field.
  • At least 5 years of hands-on laboratory experience in photonics, semiconductor, or optoelectronic device testing.
  • Experience with commercial wafer-testing stations and electrical or radio-frequency probing of semiconductor devices.
  • Experience aligning optical lenses or fibers to semiconductor devices.
  • Strong understanding of silicon photonic devices, including modulators, photodetectors, passive optical structures, and optical coupling techniques.
  • Experience developing automated laboratory or production test systems using Python or comparable programming languages.
  • Strong hands-on experience with radio-frequency and microwave measurement techniques, including vector network analyzers, S-parameters, RF probing, calibration, and de-embedding.
  • Experience with data plotting and analysis software such as JMP, MATLAB, or Python.
  • Strong expertise in RF and microwave test and measurement, including VNAs, S-parameters, RF probing, calibration, de-embedding, transmission lines, and signal integrity.
  • Strong working knowledge of optical test equipment, including tunable lasers, optical power meters, optical spectrum analyzers, polarization controllers, optical switches, and fiber alignment systems.
  • Proficiency in Python or similar programming languages for test automation, instrument control, data acquisition, analysis, and visualization.
  • Strong troubleshooting and root-cause-analysis skills across optical, electrical, RF, mechanical, software, and semiconductor-device domains.
  • Ability to transfer specialized knowledge and develop documentation, procedures, training materials, and reference methodologies that enable others to work independently.
  • Ability to guide engineers through experimental design, measurement setup, debugging, data interpretation, and root-cause analysis.
  • Ability to teach complex RF, photonics, and measurement concepts through technical explanation and hands-on laboratory coaching.
  • Ability to attend required safety training, follow site and corporate EHS procedures, and use required personal protective equipment.
Responsibilities
  • Provide technical leadership for the development, implementation, and continuous improvement of silicon photonics wafer-level test and characterization methodologies for photonic integrated circuits and associated test structures.
  • Develop and optimize wafer-level characterization methods for active and passive silicon photonic devices, including modulators, photodetectors, waveguides, couplers, resonators, and integrated photonic circuits.
  • Lead RF and high-speed electro-optical wafer characterization, including S-parameter measurements, frequency response, bandwidth, impedance characterization, calibration, de-embedding, and signal-integrity analysis.
  • Develop robust methods for automated optical alignment and coupling at wafer level, emphasizing measurement accuracy, repeatability, stability, and test throughput.
  • Develop and maintain test automation and data-analysis software, including instrument control, wafer navigation, optical alignment, test sequencing, error handling, and automated data processing.
  • Analyze wafer-level characterization data and wafer maps to identify device distributions, spatial trends, process variation, systematic effects, yield limiters, and test-related artifacts.
  • Partner with device design, process integration, and foundry teams to correlate wafer-test results with device physics, fabrication processes, process-control monitors, and design parameters.
  • Collaborate with photonics design, RF/analog design, process integration, foundry, packaging, reliability, product engineering, manufacturing, and equipment suppliers to resolve technical issues and support product development and production ramp.
  • Analyze characterization datasets to identify performance distributions, process sensitivities, correlations, failure mechanisms, and opportunities to improve device performance and test efficiency.
  • Define test structures and characterization requirements in collaboration with the silicon photonics and design team.
  • Drive design-for-test improvements and influence future device and photonic integrated circuit designs based on characterization results and test limitations.
  • Lead root-cause investigations for complex electrical, RF, optical, and electro-optical performance issues.
  • Serve as a technical mentor and coach for junior and mid-career engineers.
  • Review test plans, measurement methodologies, automation code, data analysis, and technical conclusions produced by other engineers, providing technical feedback and guidance.
  • Delegate technically challenging projects to develop engineering capability while maintaining appropriate technical oversight.
  • Attend required safety training, follow applicable quality and environmental management procedures, and support relevant ISO standards as assigned.

About the company

Coherent designs and sells lasers, laser-based technologies, and complete laser system solutions for commercial, industrial, and scientific uses. Its products include laser sources and components, as well as turnkey systems for applications such as microelectronics manufacturing, materials processing, medical diagnostics, and research; revenue comes from hardware sales, services, and recurring consumables and software. It serves OEMs, end-users, and government agencies worldwide, competing by offering a broad, integrated portfolio of laser products and system solutions across multiple industries. Its goal is to expand product lines and services to help customers deploy and scale laser-based technologies in manufacturing, research, and defense applications.

Company Size

5,001-10,000

Company Stage

IPO

Headquarters

Santa Clara, California

Founded

1966

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Simplify's Take

What believers are saying

  • FY2026 revenue hit $7.12 billion, up 23%, with Q4 up 34%.
  • Management guided Q1 FY2027 revenue to $2.2 billion-$2.4 billion on August 12, 2026.
  • Coherent says customer visibility extends into 2028, with long-term agreements reaching decade-end.

What critics are saying

  • Q4 FY2026 Datacenter and Communications supplied 79% of revenue; AI digestion hurts hard.
  • PhotonLink revenue ramps in Q4 CY2026, leaving execution risk through 2027.
  • Hyperscalers can dual-source or insource optics, crushing Coherent's pricing power by 2028.

What makes Coherent unique

  • September 21, 2026 PhotonLink bundles lasers, silicon photonics, assembly, and test.
  • Coherent sells complete optical systems, not just parts, speeding customer qualification.
  • Its InP lasers, VCSEL arrays, specialty fibers, and modules span AI architectures.

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Benefits

Hybrid Work Options

Growth & Insights and Company News

Headcount

6 month growth

26%

1 year growth

-7%

2 year growth

-10%
Compound Semiconductor
Sep 22nd, 2026
BluGlass to collaborate with Coherent.

BluGlass to collaborate with Coherent. Tuesday 22nd September 2026 Companies to develop novel GaN-based device for emerging scientific and medical applications Australian firm BluGlass has entered into an early-stage collaboration with photonics giant Coherent Corp to co-develop a novel GaN-based device targeting scientific and medical markets. This initial feasibility study is expected to run for three to five months and will evaluate the compatibility of the companies' proprietary processes. Valued at $200k, the collaboration combines BluGlass' complementary expertise in proprietary GaN epitaxial growth and semiconductor laser development with Coherent's leadership in photonics, advanced manufacturing, and market access. Under the agreement, the companies will jointly evaluate device architectures and manufacturing techniques to enable high-performance visible wavelength lasers for demanding scientific instrumentation and medical applications. Initial development discussions have commenced, including device architecture options, epitaxial structure designs, and process integration. BluGlass CEO Jim Haden said: "Coherent's decision to collaborate with BluGlass is a strong vote of confidence in its GaN epitaxy and laser capabilities, reinforcing its growing industry reputation for developing differentiated technology solutions to support next-generation applications. "While the initial phase of this collaboration focuses on advancing a novel device architecture, it has the longer- term potential to address high-value opportunities in scientific and medical applications. The collaboration with this industry leader expands our GaN laser portfolio and, more importantly, extends our reach into key scientific and medical markets that demand precision photonic performance."

Industrial AI Technology
Sep 21st, 2026
Coherent showcases new optical innovations to scale AI infrastructure at ECOC 2026.

Coherent showcases new optical innovations to scale AI infrastructure at ECOC 2026. 17 hours ago Coherent has unveiled a wide range of new optical technologies and live demonstrations aimed at helping customers scale AI infrastructure, at ECOC 2026 in Málaga. Coherent Corp. (NYSE: COHR) has announced new optical technologies and live demonstrations designed to help customers scale AI infrastructure, at the European Conference on Optical Communication (ECOC) 2026 in Málaga, Spain. At Stand 2100, Hall 2, Coherent is showcasing innovations spanning AI data centre connectivity, co-packaged optics (CPO) and near-packaged optics (NPO), next-generation pluggable transceivers, optical transport, specialty fibres, optical circuit switching, advanced materials, and thermal management for rising power density. The company also introduced PhotonLink, a new integrated optics platform bringing together Coherent's optical technologies and integration capabilities to support CPO, NPO and emerging chip-to-chip connectivity, combining components and complete optical assemblies with manufacturing at scale. Further details on PhotonLink are due to be announced separately. "Scaling AI infrastructure requires more than bandwidth, it requires solving power, integration and thermal challenges together," said Dr. Sanjai Parthasarathi, Chief Marketing Officer at Coherent. "At ECOC, we are demonstrating how Coherent's expertise across materials, components and optical systems helps customers address those challenges, from connections near compute to links between data centres." Featured technology demonstrations. Coherent's demonstrations show how its vertical integration across materials, devices, components, modules and systems supports different AI connectivity architectures, including scale-across, scale-out, scale-up and chip-to-chip. Highlights include a compact 3.2T pluggable transceiver with dual 1.6T optical paths in an OSFP-size package, using eight 425G PAM4 line-side optical lanes, Coherent's differential EMLs and photodiodes, pointing toward next-generation 400G-per-lane optical connectivity; a 6.4T NPO optical engine combining silicon photonics, fibre attach technology, ELSFPs and Coherent laser technology for high-density AI scale-up and scale-out fabrics; high-density 2D VCSEL and photodiode arrays for parallel optical architectures in CPO and NPO low-latency connectivity; and the LS200 full C-band pluggable optical line system for datacentre interconnect and transport applications. Optical components, assemblies and modules. Coherent is also showcasing a range of new products and emerging technologies, including FlexConnect, a detachable fibre array unit connector for CPO applications; OptiAlign, a high-precision fibre array unit for CPO applications; OptiFocus, a two-in-one coupling lens design for ELS; FiberPack, a passive fibre assembly kit for scale-up and scale-out architectures; OptiPolar Array X, a multi-channel polarization beam splitter array; a 2D micro-VCSEL and photodiode array for NPO or CPO architectures; specialty fibres including polarization-maintaining, mode-matched and multi-core fibre; an ultra-high-power continuous-wave laser; and the Pluggable Optical Line System (POLS), a full C-band optical line system supporting up to 32 DWDM wavelengths and up to 25.6 Tbps over links from 2km to 200km. Thermal management and partner demonstrations. Coherent is also showing Thermadite materials, diamond-based solutions and other advanced materials designed to address the growing power density and cooling needs of AI infrastructure. Alongside partner Quside, the company is demonstrating quantum random number generation for encryption using live quantum entropy, and with CUbIQ, Coherent is taking part in a quantum key distribution demonstration in a compact pluggable architecture. Coherent executives are also contributing to the ECOC technical programme and Market Focus sessions throughout the week, covering topics including AI data centre infrastructure, CPO, optical interconnect scaling, advanced materials, coherent-lite optics and satellite connectivity. Visitors can see the demonstrations and meet Coherent's team at Stand 2100, Hall 2, FYCMA, Málaga, from 21 to 23 September.

Associated Press
Sep 20th, 2026
Coherent unveils PhotonLink platform and 6.4T NPO optical engine for AI datacenters at ECOC 2026

Coherent Corp. unveiled new optical technologies at the European Conference on Optical Communication 2026 in Málaga, Spain, targeting AI infrastructure scaling challenges. The photonics company showcased PhotonLink, a new integrated optics platform supporting co-packaged optics, near-packaged optics, and chip-to-chip connectivity. Key demonstrations included a 3.2T transceiver in an OSFP-size package with dual 1.6T optical paths, a 6.4T NPO optical engine for high-density AI fabrics, and VCSEL-based optics for AI scale-up. Coherent also presented its LS200 full C-band pluggable optical line system for datacenter interconnect applications. The company displayed thermal management solutions through Thermadite materials and diamond-based components addressing AI infrastructure cooling requirements. Coherent executives participated in market focus sessions covering AI datacenter infrastructure, co-packaged optics, and optical interconnect scaling throughout the conference.

Yahoo Finance
Sep 19th, 2026
Coherent launches compact optical system for AI datacenters after 34% revenue surge

Coherent Corp. announced an upgraded Pluggable Optical Line System that fits into a compact QSFP module. The system can pack 32 wavelengths onto a single fibre pair, delivering up to 25.6Tbps of traffic on links running 2km to 200km. It's designed for 800G coherent optics and is already shipping in high volume in 400G and 800G versions. The launch follows strong financial results. On 12 August, Coherent reported fiscal fourth-quarter revenue of $2.05 billion, up 34% year-on-year. Non-GAAP earnings per share rose to $1.74 from $1.00. CEO Jim Anderson noted AI data centres are increasingly moving from copper to optical links. However, the company faces valuation concerns. Its forward P/E stands at 31.25, whilst hedge fund holdings dropped to 105 from 114 in the prior quarter.

Insider Monkey
Sep 19th, 2026
Coherent (COHR) squeezes key optical network gear into a plug-in module.

Coherent (COHR) squeezes key optical network gear into a plug-in module. Published September 19, 2026 at 8:35 am EDT On September 17, Coherent Corp. (NYSE:COHR) announced an upgraded Pluggable Optical Line System that covers the full C-band and fits in a compact QSFP module, the same slot ordinary transceivers use. That is a lot of networking gear shrunk into a plug, and it follows a quarter of 34% revenue growth. Here is what the launch means, and where the stock's story gets harder to read. Big pipe, small plug. Start with what the product does. The upgraded system can pack 32 wavelengths onto a single pair of fibers, which Coherent says adds up to as much as 25.6Tbps of traffic on links running 2km to 200km. It is designed for the latest 800G coherent optics, and it configures itself, handling link setup and laser safety without a technician tuning each connection. Coherent also says the system is generally available and already shipping in high volume, in 400G and 800G versions that work with existing network setups. Madhu Krishnaswamy, who runs the company's telecom transport unit, describes the goal as easing the usual trade-off between raw performance and operational simplicity. The launch also sits on top of a business that is already moving. On August 12, Coherent reported results for its fiscal fourth quarter, which ended June 30: revenue of $2.05 billion, up 34% from a year earlier. Non-GAAP earnings per share rose to $1.74 from $1.00, and CEO Jim Anderson noted that for the full year, that measure grew more than twice as fast as revenue. Management guided to revenue of $2.2 billion to $2.4 billion for the first quarter of fiscal 2027, and Anderson says AI data centers are increasingly moving from copper to optical links. The catch behind the numbers. Now look at the two versions of profit. Coherent's non-GAAP earnings came to $1.74 per share, but under GAAP the figure was $1.19. The gap comes from items management leaves out, including stock-based pay, amortization on acquired intangibles, and restructuring and integration costs. Operating margin shows it more clearly, at 21.8% on a non-GAAP basis and 12.4% under GAAP. Some of those costs are non-cash, but they are real, and anyone anchoring on the higher figure is skipping them. Then there is how much weight this launch can carry. The announcement puts no sales figure on the product, so its contribution to a company that booked $2.05 billion in a quarter cannot be sized from what has been published. The bullish story also rests on management's own read of where AI networks are headed, and on a capacity build-out that CFO Sherri Luther says gets priority in spending. Money spent on capacity only pays off if the demand management describes keeps arriving. Fewer funds, real skeptics. Hedge funds holding Coherent slipped to 105 from 114 in the prior quarter. That suggests some big holders are trimming. Short interest is 6.44% of the float, enough for a real group of skeptics but not a crowded bet. Some of it may be hedging, so it is a softer signal than the fund count. The forward P/E is 31.25, as of September 18, so investors are paying up for growth even as fewer funds hold on. Growth versus the price tag. Coherent is aiming at the shift from copper to optical inside AI datacenters, and its results so far show sales and profit growing quickly alongside a product already shipping in volume. Against that sit a demanding valuation and two versions of profit that tell different stories. Bulls need optical demand from AI infrastructure operators to keep growing and products like this one to become visible revenue, while bears are watching for growth to cool as the costs outside the non-GAAP numbers stay put.