הרצאת המכון ללימודים מתקדמים ע"ש סאקלר

פרופסור אמנון יריב

פרופסור לאלקטרוניקה ע"ש תומס מאירס, המחלקה להנדסה ומדע שימושי, המכון הטכנולוגי של קליפורניה, פסדנה, קליפורניה, ארה"ב

Professor Amnon Yariv Thomas Myers

Professor of Electrical Engineering and Applied Physics California Institute of Technology Pasadena, California, U.S.A.

Lecture:

"A TALE OF TWO LASERS" - A new generation high coherence Semiconductor Lasers

Light refreshments will be served at 14:40 before the lecture

Abstract: 
The semiconductor laser is technologically and, increasingly scientifically, the most important of all the laser types. This distinction is due to a large extent to the fact that it is essentially an electronic component , fully compatible with semiconductor based electronics. Near 100% efficient and Fast (10-11s). In an embodiment known as the Distributed Feedback (DFB) laser it has become the primary light source for the world-wide fiber optic internet network.

The increasing demands for bandwidth on the part of the Internet are now pushing the DFB laser to the limits of its capabilities. The main problem is the transition to phase-coherent communication which requires a far larger temporal coherence that possessed, by the DFB laser.

The talk will review the quantum limits of phase coherence in lasers in general and in semiconductor lasers in particular. I will describe the quantum noise limitations of the present DFB laser, incidentally developed at Caltech in the mid 70's, and will show that the basic double heterostructure design, taken as given for the last 40 years, is the wrong design from the point of view of coherence. A new laser design based on a Si/III-V platform and its rationale will be described. The first generation fabricated in our Laboratory and the coherence measurement will be described. Coherence levels, characterized by the Schawlow-Townes linewidth, which are higher by more than order of magnitude compared to the best commercial lasers now in use, are measured on the first generation of these lasers.