Silicon Photonics and Lasers Technologies in 100G QSFP28 Transceivers
Updated at Feb 5th 20251 min read
The dominance of 100G network architecture continues to shape the data-driven market landscape, with its associated technologies evolving at an unprecedented pace. Laser-based solutions, long regarded as the gold standard for 100G QSFP28 optical modules, maintain strong market adoption due to their proven reliability and cost-efficiency. Meanwhile, silicon photonics technology — a disruptive innovation — has steadily gained traction through years of R&D breakthroughs, demonstrating transformative potential in high-density, low-power optical transceivers. This comparative analysis delves into the technical merits, scalability challenges, and future trajectories of both silicon photonics and conventional laser technologies within next-generation 100G QSFP28 ecosystems.
Lasers in 100G QSFP28 Transceivers
From the above, we understand the impact of silicon photonics technology on 100G transceivers and future 400G networks, but the application of other traditional laser technologies in transceivers relative to silicon photonics technology also occupies a certain market position. We can learn more about laser technology for QSFP28 100G transceivers here.
Typical Laser Types and Characteristics
Lasers are the core devices of optical transceivers, which inject current into semiconductor materials and inject laser light through the photon oscillations and gains in the resonator. The laser occupies 60% of the cost of the transceiver module, closely relating to the transmission distance of the transceiver. Typical laser types in the market include VCSEL, FP, DFB, DML, and EML. The table below shows their wavelengths, working patterns, and applications.
Laser | Wavelength | Working Pattern | Application |
VCSEL | 850nm | Surface Emitting | <200M |
FP | 1310nm/1550nm | Edge Emitting | 500M-10KM |
DFB | 1310nm/1550nm | Edge Emitting | 40KM |
DML | 1310nm/1550nm | Direct Modulation | 500M-10KM |
EML | 1310nm/1550nm | External Modulation; Electro Absorption Modulation | 40KM |
Applications of Lasers in 100G QSFP28 Modules
Among these, three laser types—VCSEL, EML, and DML—are widely used in 100G QSFP28 transceivers:
VCSEL: Compact, high coupling efficiency, low power consumption, and cost-effective. It is commonly used in 100G QSFP28 SR4 transceivers, optimized for multimode fiber networks.
EML: Offers superior wavelength stability and minimal dispersion, with frequency response reaching beyond 40 GHz. It is widely deployed in 100G QSFP28 ER4 and LR4 transceivers, supporting single-mode fiber (SMF) for transmission distances up to 10km.
DML: Mainly suitable for lower speeds (≤25Gbps) and shorter distances (2-10km). Due to limitations in chromatic dispersion, frequency response, and extinction ratio, DML lasers are commonly used in 100G QSFP28 CWDM4 transceivers for 2km CWDM applications.
DML and EML lasers are widely used in different transceivers, with the primary distinction being DML’s simpler single-chip design, while EML integrates an electro-absorption modulator (EAM) for better high-speed performance. Learn more about their differences here: EML vs. DML: Essential Laser Technologies in 100G/200G/400G/800G Optics.
Key Constraints of Laser Technology
Despite their established role in 100G QSFP28 transceivers, traditional laser technologies face several inherent limitations. For example, while DMLs offer a simpler single-chip design and lower power consumption, they are prone to increased chromatic dispersion and a limited frequency response that restricts their effective reach to shorter distances (typically under 10 km). In contrast, EMLs—despite delivering superior wavelength stability and high-speed performance—require the integration of an electro-absorption modulator, which not only adds complexity to the design but also drives up production costs. Moreover, both laser types necessitate precise integration with electronic circuits to preserve signal integrity, with challenges in thermal management and packaging further complicating scalability. These constraints highlight the trade-offs between performance, cost, and design simplicity that must be carefully balanced in next-generation optical transceiver development.
Silicon Photonics in 100G QSFP28 Modules
Overview of Silicon Photonics Technology
Silicon photonics is a breakthrough optical technology that primarily utilizes silicon-on-insulator (SOI) wafers as semiconductor substrate materials and integrates CMOS manufacturing processes, reducing power consumption while enhancing the transmission performance of optical modules. Currently, silicon photonics transceivers in the market are mainly categorized into short-distance and long-distance transmission types.
Short-Distance Transmission:
100G QSFP28 DR1 (SiPh) is applicable to two short-distance scenarios:
Replacing 100G QSFP28 PSM4 (500m): The cabling is optimized, reducing costs by transitioning from MPO-8 fiber jumpers to dual-core LC fiber.
Replacing 100G QSFP28 CWDM4 (500m, OCP): The fiber optic infrastructure remains unchanged.
Long-Distance Transmission:
100G QSFP28 LR1 (SiPh) can directly replace 100G QSFP28 LR4, enabling long-distance 100G transmission of 10km and 20km.
Advantages of Silicon Photonics in 100G QSFP28
Compared to conventional InP-based laser technologies (e.g., DFB, EML), silicon photonics offers:
CMOS compatibility: Enables large-scale integration of photonic devices and electronic circuits.
Cost efficiency: Silicon substrates follow Moore’s Law, doubling transistor density annually (vs. InP’s 2.6-year cycle).
Power optimization: Photonic integrated circuits (PICs) minimize heat generation, critical for high-density deployments.
Wavelength flexibility: Silicon nitride waveguides extend transmission distances by supporting diverse wavelength ranges.
Challenges of Silicon Photonics in 100G QSFP28
While silicon photonics technology offers significant advantages for 100G QSFP28 transceivers, several challenges must be addressed for effective implementation:
Packaging Complexity: The transition from silicon photonics chips to fully packaged optical modules presents technical difficulties. Packaging yield and cost optimization remain areas for improvement.
Laser Integration: Silicon is an indirect bandgap semiconductor, making it inefficient for direct light emission. External light sources are required, which do not follow Moore’s Law. Additionally, as integration levels increase, costs rise, potentially offsetting the cost benefits of silicon-based materials and processing.
Power & Thermal Sensitivity: Silicon photonics chips are more temperature-sensitive than traditional transceivers. To enhance cost-effectiveness, further optimization of power consumption and thermal design is required in silicon photonics-based optical modules.
Silicon Photonics vs. Laser: Market Outlook and Collaborative Trends
Laser Technology: Pursuing Higher Integration and Stability
Traditional laser technologies, such as Directly Modulated Lasers (DML) and Electro-Absorption Modulated Lasers (EML), have been integral to 100G QSFP28 transceivers. However, challenges related to design complexity and cost are driving the industry toward innovation. Future developments aim to optimize integration, reduce power consumption, and enhance transmission stability. This includes refining electro-absorption modulators to meet the demands of higher data rates and longer transmission distances, thereby ensuring stable signal output in high-density deployments.
Silicon Photonics: Dominating Future High-Speed Networks
The increasing demand for high-performance, low-power transmission solutions in data center networks has accelerated the adoption of silicon photonics technology. According to a 2022 report by Vantage Market Research, the silicon photonics market is projected to grow at a compound annual growth rate of approximately 25.8% through 2028. Companies like Intel are rapidly advancing in the silicon photonics transceiver sector, indicating potential for surpassing traditional optical modules in terms of transmission speed, energy efficiency, and cost-effectiveness.

Synergy in Action: Bridging Laser Precision with Silicon Scalability
The convergence of silicon photonics and laser technologies is poised to revolutionize the optical module industry. By leveraging the strengths of both, current 100G modules can achieve more cost-effective transmission solutions, facilitating the implementation of 400G interconnect technologies. This synergy is expected to significantly enhance data center network performance in terms of transmission speed and energy efficiency, propelling the industry toward higher speeds and lower power consumption.
Conclusion
As traditional laser and silicon photonic technologies jointly push the industry toward higher density and lower power consumption, FS offers a comprehensive portfolio of optical modules to meet diverse data center needs. Our FS laser-based 100G QSFP28 transceivers deliver agile, future-ready solutions through innovative yet practical designs. Validated across 200+ live devices with adaptive FS Box coding, these modules ensure plug-and-play compatibility across Cisco, Arista, and Juniper ecosystems, while optimized DML/EML designs achieve power efficiencies of less than 3.5W—ideal for high-density deployments.
In addition, FS provides cutting-edge 400G silicon photonic modules that extend reach and scalability for next-generation interconnects. Leveraging advanced silicon photonics technology, these modules overcome conventional speed and energy efficiency limitations and simplify the transition from 100G to 400G architectures.
Together, FS laser and silicon photonic modules empower enterprises to balance performance, energy savings, and total cost of ownership, paving the way for agile, cost-effective, and future-proof data center architectures.