As silicon photonics (SiPh) and photonic integrated circuit (PIC) technology continues to evolve, new optoelectronic devices emerge to meet the demand for higher bandwidth, lower power consumption, and reduced latency in high-speed data communication applications like network switching and high-performance computing (HPC). However, despite their sophistication, these devices do not inherently have the reliability needed to withstand ever harsher operational environments, let alone when deployed at scale. Without rigorous reliability testing, potential failures and performance degradation could lead to costly downtime and reduced device lifespan.

Packaging Trends Increase Stress Factors for PIC Devices

Among the various optoelectronic PIC components used in the field, active devices such as laser diodes, optical modulators, and photodiodes are particularly prone to reliability issues due to increasingly demanding operation scenarios. The projected roadmap for optics packaging —from conventional pluggable optics toward state-of-the-art co-packaged optics (CPO)—entails aggressive shrinkage of PIC chiplet sizes. This results in higher power density concentrated in small areas, creating a stressful thermal environment for these miniaturized PIC devices.

Key Reliability Challenges for Active SiPh/PIC Devices

Compound semiconductor-based laser diodes are the typical light source used for PICs. Their relatively immature manufacturing process (compared to silicon (Si) processing) makes them susceptible to microcracks during facet cleaving. The subsequently formed dark line defects (DLDs) sprawl along the crack plane until the laser diode eventually fails in its entirety. 

Another widely deployed active PIC device is the optical modulator. Phase devices such as micro-ring modulators are inherently sensitive to temperature variations and need heaters to compensate for temperature shifts induced by thermal agitation. These heaters are typically fabricated through a metallization process, which is cost-effective but comes at the price of a metal-specific reliability issue: electromigration, a metallic degradation phenomenon that occurs when current density scales to MA/cm2 levels. 

Lastly, photodiodes used in PIC receiver subassemblies are also vulnerable to reliability issues. High-speed germanium (Ge) photodiodes in particular suffer from lattice mismatch between Ge deposition and Si substrate, introducing defects that contribute to dark current degradation. For all these devices, stringent reliability testing can deliver substantial benefits in terms of mitigating failure risks, cutting capex, and reducing cost-of-ownership.

Chroma's Reliability Test Solutions for SiPh/PIC Manufacturing

Chroma ensures customer success by aiding in the development of innovative technology products while maintaining performance and quality standards. Chroma's 58604 and 58606 Series of PIC Burn-in and Reliability Test Systems offer aging, reliability, and lifetime testing for a variety of photonic chip components such as laser diodes, photodiodes, and optical modulators. These systems boast a testing capacity of up to 1,792 channels with 28 independent temperature control modules, each providing bi-polar voltage and current outputs and measurements across 64 SMU channels.

For more detailed product information, please visit the Chroma website and leave your inquiry and contact details. We are happy to be of service.