VCSEL: Vertical Cavity Surface Emitting Laser.
VCSEL's laser resonator consists of two distributed Bragg reflector (DBR) mirrors with high reflectance >99%. This high reflectance is required to compensate for the short axial length of the gain region.
Advantages (compared to edge-emitters, of course):
1. Laser cavity is short (1~1.5 λ), so only one longitudinal mode can oscillate. (The longitudinal mode spacing is λ/2).
2. The high reflective resonator mirrors results in low threshold current so VCSEL has lower power consumption. (However lower output optical power.)
3. λ vs. T (<0.1 nm/K) is ~5 times smaller than edge emitters (0.2~0.3 nm/K).
4. Easier thermal dissipation and high T operation.
5. Circular output beam. This brings easier beam shaping, easier fiber-coupling, etc.
6. High reliability. VCSEL is not subject to catastrophic optical damage (COD).
7. When put in external-cavity, EC-VCSEL has no mode-hops during tuning or modulation because of the large mode-spacing.
Disadvantages:
Need to do more search on this.
The brightness of the high-power VCSEL is still lower than edge-emitters (why?)
References:
[1] Princeton Optronix website.
[2] http://en.wikipedia.org/wiki/VCSEL
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The VCSEL market is expected to grow at a CAGR of 17.3% during the forecast period and is expected to be valued at USD 3,124.1 Million by 2022. VCSELs are used in a wide range of applications, owing to their advantages such as compact size, high reliability, low power requirements, and low manufacturing costs. Also, the growing applications of automobiles that use electrical systems in the automotive industry is driving the growth of the overall VCSEL market.
http://www.marketsandmarkets.com/pdfdownload.asp?id=206588268
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