OFC 2026 - >+25-dBm x 8-Channel SOA-Integrated DFB-LD TOSA for CPO - Furukawa Electric Co., Ltd.
At OFC 2026, Furukawa Electric presented a breakthrough external laser source (ELS) for co-packaged optics (CPO). As silicon photonics (SiPh) modulators move to higher speeds, required optical power has risen from +20 dBm to above +23 dBm. Furukawa's high-power 8-channel TOSA not only delivers +25 dBm per channel under cooled conditions, but also sets a new industry benchmark for thermal design and reliability.
Core Technology: 1.8 mm Long Cavity and SOA Integration
To break through the power bottleneck of conventional lasers, Furukawa redesigned its distributed-feedback laser diode (DFB-LD) with an integrated semiconductor optical amplifier (SOA).
1. A Long-Cavity Architecture That Lowers Thermal Resistance
Conventional lasers generate large amounts of heat under high current injection, which degrades efficiency. Furukawa extended the cavity length from 1 mm to 1.8 mm.
Thermal-resistance optimization: the longer cavity lowers thermal resistance and suppresses temperature rise under high current injection.
Chip-level performance: at a substrate temperature of 25 degC, a single DFB-LD chip delivers more than 450 mW.
2. 8-Channel TOSA Package Construction
The assembly mounts eight laser chips junction-down on an aluminum nitride (AlN) substrate to further improve heat dissipation.
Integrated optical isolator: a new lens-integrated optical isolator simplifies assembly and improves reliability.
Precision coupling: sub-micron alignment delivers stable fiber-coupling efficiency above 80%.
Data Deep Dive: Balancing Power and Temperature
Furukawa stressed that long-term laser reliability depends on keeping the junction temperature within 65 degC. The table below compares performance in two operating scenarios:
Metric | Cooled | Uncooled |
Case temperature | 25 degC | 55 degC |
LD bias current | 1000 mA | 870 mA |
Estimated laser temperature | 37 degC | 65 degC (reliability limit) |
Fiber-coupled power | > +25 dBm / ch | > +23 dBm / ch |
Power conversion efficiency (PCE) | 19.6% | 15.5% |
Noise Performance (RIN)
Protected by the integrated optical isolator, the TOSA keeps relative intensity noise (RIN) below -155 dB/Hz with or without -17 dB optical reflection. This is critical for signal integrity in higher-order modulation such as PAM4 or coherent.
Supply Chain and Market Impact
Solving CPO's power bottleneck: CPO packages the optical engine together with the ASIC, and the resulting heat forces the laser source to be external (ELS). Furukawa's +25 dBm output means a single ELS module can feed more modulators through splitting, lowering total system cost and power.
Standardization: the technology maps directly to the UHP (Ultra High Power) and SHP (Super High Power) classes in the OIF ELSFP IA. This will accelerate ELSFP module deployment in 1.6T and even 3.2T switches.
Supply-chain position: with its vertical design capability integrating SOA and DFB, Furukawa strengthens its lead in high-power laser chips, directly shaping the optical foundation of next-generation AI data center switches.
Simple Tech Trend's Take
The key to Furukawa's demo is not just "high power" but a "manufacturable thermal balance". SOA-integrated lasers have often been limited by thermal crosstalk and could not run stably above 55 degC. Using a 1.8 mm long cavity and junction-down packaging, Furukawa squeezes out +23 to +25 dBm while staying within industrial reliability limits (65 degC junction temperature).
Over the next 12-18 months, we expect the market's focus to shift from "can the laser light up" to "how to lower cost per dB". If Furukawa's 8-channel solution can sustain a PCE near 20%, it will be a highly attractive component for NVIDIA or Broadcom as they push CPO. We predict ELS modules will be among the highest-margin segments of the optical supply chain in 2026-2027.
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