News: Optoelectronics
31 July 2025
HieFo unveils HOT25 specialty DFB laser chip for OTDR systems
Indium phosphide (InP)-based optical communications device developer and manufacturer HieFo Corp of Alhambra, CA, USA (formed from management buy-out of the chips business and wafer fabrication operations of Emcore Corp in May 2024) has announced the commercial release of its new HOT25 specialty distributed feedback (DFB) laser chip, engineered specifically for optical time domain reflectometer (OTDR) applications in fiber-optic test & measurement equipment. HieFo says that, like most other products in its portfolio, the OTDR product is the result of an in-house R&D project without relying on any legacy technology from Emcore.
Optimized for use at 25°C, the HOT25-01-1310 delivers high output power of 300mW at a wavelength of 1310nm, suiting OTDR applications. Designed with a 1mm cavity length and leveraging HieFo’s proprietary low-noise laser architecture, the chip is built to meet the demanding needs of high-resolution OTDR systems while ensuring reliable field performance.
HieFo says that, compared with other OTDR laser chips on the market, the HOT25 chip has compact size (250μm width x 1000μm length x 100μm thickness) and advanced performance, achieving the same high output with a significantly shorter 1mm chip length, demonstrating superior efficiency and thermal management.
Moreover, most competing OTDR chips use FP (Fabry–Pérot) lasers that emit multiple wavelengths simultaneously. In contrast, the HOT25 is a true DFB laser that operates at a single wavelength with narrow linewidth. So, while conventional FP lasers are limited to time-of-flight (ToF) detection, HieFo’s single-wavelength DFB laser supports frequency-modulated continuous wave (FMCW) coherent detection. This allows more precise and longer-range OTDR measurements, unlocking new applications in coherent OTDR systems.
Other key features are listed as:
- excellent spectral purity, with >50dB side-mode suppression ratio (SMSR);
- low relative intensity noise of –145dB/Hz½;
- RoHS compliant and robust under operating conditions from 0°C to 50°C.
The HOT25 laser chip is available now for immediate sampling and volume orders.
HieFo launches high-efficiency CW DFB InP lasers for silicon photonics transceivers
