Biography
Connie Jui-Hua Chang-Hasnain’s groundbreaking contributions to the physics and design of vertical cavity surface emitting lasers (VCSELs) have been instrumental in establishing VCSELs as the dominant technology for multimode fiber applications. Used in applications ranging from Ethernet data networks to computer mice to laser printers, VCSELs can be turned on and off very fast and manufactured at very low cost in wafer-scale. Dr. Chang-Hasnain explained the modal structure of VCSELs and demonstrated the first planar structure, which was commercialized. She was first to demonstrate multi-wavelength VCSEL array for multimode-fiber interconnects and 140-wavelength array with precise wavelength variation. She developed the first tunable VCSEL structure with a wide tuning range and later invented a high-contrast grating, which led to a tunable laser with a 160x speed improvement.
Connie Jui-Hua Chang-Hasnain and Fumio Koyama laid the foundation for VCSEL photonics, resulting in critical breakthroughs and opening doors to industrial applications that have had a significant impact on high-speed optical interconnects and optical sensing. With more than 2.1 billion devices deployed, VCSELs are by far the most pervasive type of laser today. Chang-Hasnain and Koyama mostly conducted independent research, but they collaborated and influenced each other’s research. They also worked closely to organize international education programs and conferences such as iNOW. Their seminal work on the fundamentals and new functionalities of VCSELs created technology breakthroughs with lasting impact. Koyama realized the first room-temperature continuous wave (CW) operation of VCSELs in 1988, igniting research activities worldwide. Without his contributions, the realization of room temperature operation for VCSELs would have faced significant delays. Furthermore, his meticulous measurements of laser linewidth, intensity noise, polarization control, and single-mode characteristics played a pivotal role in achieving CW operation. Simultaneously, Chang-Hasnain provided invaluable theoretical guidance on the structure of transverse and longitudinal modes and demonstrated the first successful multimode fiber transmission. The combined efforts of Chang-Hasnain and Koyama established the foundational principles of VCSELs. Tunable VCSELs, particularly tunable micro-electromechanical systems (MEMS) VCSELs, have opened up numerous applications, including micron-level depth measurement in swept-source optical coherence tomography, with implications in ophthalmology, dermatology, cardiology, and gastroenterology, as well as in biomedical and pharmaceutical analysis. In 1995, Chang-Hasnain demonstrated the first widely tunable, swept MEMS VCSEL, and she also pioneered the development of HCG-based MEMS-VCSEL with the fastest swept speed. In addition, Chang-Hasnain realized the first VCSEL arrays at 940 nm for 3D imaging in 1998, which are now deployed in smart phones worldwide for facial recognition applications. Multi-Mode Fiber (MMF) MM-VCSEL transmission has now been widely adopted in data centers and supercomputers. In short, VCSELs play a critically important role in many applications, including optical communications, sensing systems, biophotonics, medical imaging, consumer electronics, and LIDAR with a projected market value of over $10 billion. The field of VCSELs owes much of its vibrancy to the groundbreaking work of Chang-Hasnain and Koyama.
An IEEE Fellow, Chang-Hasnain is the Whinnery Chair Professor Emerita, University of California Berkeley, Berkeley, California, USA, and is the 2024 co-recipient of the IEEE Nick Holonyak, Jr. Medal for Semiconductor Optoelectronic Technologies for "pioneering contributions to vertical-cavity surface-emitting laser (VCSEL) and VCSEL-based photonics for optical communications and sensing".
