S David Roh

Title: S David Roh: Innovator in Semiconductor Laser Technology

Introduction

S David Roh is a prominent inventor based in Allen, TX (US), known for his contributions to semiconductor laser technology. With a total of 2 patents, he has made significant advancements in the field, particularly in the design and functionality of dual-wavelength semiconductor lasers.

Latest Patents

Roh's latest patents include innovations in current biased dual distributed Bragg reflector (DBR) grating semiconductor lasers. One of his notable inventions allows for dual-wavelength operation by biasing the gain section. This design features multiple gratings spaced apart from each other, which are separated from an output aperture by a gain section. The relatively low coupling coefficient in the front grating reduces added cavity loss for the back grating mode, facilitating easier threshold achievement for the back grating mode. Additionally, the space section minimizes current-induced thermal interaction between the two uniform grating sections, significantly reducing inadvertent wavelength drift. This results in tunable mode pair separations as small as 0.3 nm and as large as 6.9 nm.

Another patent focuses on a laser heterostructure that includes an active layer, a lateral waveguide terminating in an output aperture, and a gain section with a current drive electrode. This design incorporates a rear surface distributed Bragg grating with a tuning current electrode and a front surface distributed Bragg grating, which is closer to the output aperture. The operation is optimized when the front surface distributed Bragg grating has adequate reflectivity at the Bragg wavelength while minimizing scattering loss at other wavelengths.

Career Highlights

S David Roh is affiliated with the University of Illinois, where he continues to contribute to research and development in semiconductor laser technology. His work has garnered attention for its innovative approach and practical applications in various fields.

Collaborations

Roh has collaborated with notable individuals in his field, including James J Coleman, enhancing the impact of his research through shared expertise and knowledge.

Conclusion

S David Roh's contributions to semiconductor laser technology exemplify the spirit of innovation and advancement in the field. His patents reflect a deep understanding of laser mechanics and a commitment to pushing the boundaries of technology.