1 EE232 Lecture 2-1 Prof. Ming Wu EE 232 Lightwave Devices Lecture 2: Basic Concepts of Lasers Instructor: Ming C. Wu University of California, Berkeley Electrical Engineering and Computer Sciences Dept. EE232 Lecture 2-2 Prof. Ming Wu Basic Concept of Lasers • Laser: – Light Amplification by Stimulated Emission of Radiation • Basic elements: – Gain media – Optical cavity • Threshold condition: – Bias point where laser starts to “lase” – Gain (nearly) equals loss Gain Mirror Semiconductor Laser Cleaved Facet
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EE 232 Lightwave Devices Lecture 2: Basic Concepts of Lasersee232/sp15/lectures...EE232 Lecture 2-9 Prof. Ming Wu Typical Q of Semiconductor Laser Edge-emitting laser: L=100µm, R=30%,
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EE232 Lecture 2-1 Prof. Ming Wu
EE 232 Lightwave Devices Lecture 2: Basic Concepts of Lasers
Instructor: Ming C. Wu
University of California, Berkeley Electrical Engineering and Computer Sciences Dept.
EE232 Lecture 2-2 Prof. Ming Wu
Basic Concept of Lasers
• Laser: – Light Amplification by
Stimulated Emission of Radiation
• Basic elements: – Gain media – Optical cavity
• Threshold condition: – Bias point where laser
starts to “lase” – Gain (nearly) equals
loss
Gain Mirror
Semiconductor Laser Cleaved Facet
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EE232 Lecture 2-3 Prof. Ming Wu
L-I Curve of Semiconductor Lasers • Distinctive threshold (at least in
classical lasers)
• Semiconductor laser is a forward-biased p-n junction, so mainly a current-biased device
• Threshold current : – Minimum current at which the