1. continued
Advanced Semiconductor Lab

3. New Materials
Strong temperature sensitivity ← Insufficient electron confinement in the active region
Insufficient variation of refraction index in InGaAs/InP ← severe problem in the formation of distributed Bragg reflectors for vertical cavity surface emitting lasers (VCSELs)
Quantum well structure 로는 필요한 파장 range를 얻지 못한다.
 Emerge Quantum Dot, InGaAsN, InNAsP, etc.

4. 7.4 Mode power distributed feedback lasers
Solution of incident and reflection
Reflectance for corrugation at z=0
Under phase matching conditions, △β
Semiconductor optoelectronic devices, by P. Bhattacharya

5. Semiconductor optoelectronic devices, by P. Bhattacharya

6. 7.5 Cleaved-Coupled-Cavity(C3 ) laser
Semiconductor optoelectronic devices, by P. Bhattacharya

7. Injection-locked Laser
C3 Laser
Injection-locked Laser
Semiconductor optoelectronic devices, by P. Bhattacharya

8. 7.6 Quantum well laser
Semiconductor optoelectronic devices, by P. Bhattacharya

9. Band diagram of the active region
Semiconductor optoelectronic devices, by P. Bhattacharya

10. Strained Quantum Well Lasers
Semiconductor optoelectronic devices, by P. Bhattacharya

11. 7.7 Surface-Emitting Laser
Semiconductor optoelectronic devices, by P. Bhattacharya

12. 7.10 Device fabrication Broad-area laser by cleaving
Ridge lasers are defined by photolithography and wet or dry etching
Semiconductor optoelectronic devices, by P. Bhattacharya

13. 7.11 measurement of laser characteristics
Differential gain
Near-and far field patterns
Usually, the fabricated laser is mounted on an efficient heat sink.
For high performance operations, a feedback circuit and thermoelectric cooling are provided.
It is common to determine the laser characteristics under pulsed biasing conditions.
Semiconductor optoelectronic devices, by P. Bhattacharya

14. Linearity of light current characteristics
Modulated output power P(t) = P0 [1+ms(t)] Modulation index,
Harmonic distortion
Intermodulation distortion
light-current characteristics should be as linear as possible.
Semiconductor optoelectronic devices, by P. Bhattacharya

15. 7.16 Long-wavelength semiconductor laser
Lead-salt or lead chalcogenide lasers
Population inversion can be achieved by using resonant tunneling
Tuning by changing the well and barrier parameters
Semiconductor optoelectronic devices, by P. Bhattacharya