VCSEL Industry. Babu Dayal Padullaparthi

Series resistance ohm 50 Ω 3 Ω PCE/WPE % 35–40% >40% >50% >55% Slope efficiency Watt/Amp 0.4–0.7 W/A >0.45 W/A 0.3 W/A Output power mW 1–10 mW >1000 mW <120 mW Rise and fall time nano sec <1 ns 5–10 ns Modulation speed Gbit/s >40 Gb/s >200 Gb/s not reported >200 Gb/s >25 Gb/s 3 dB down S ₂₁ bandwidth GHz >20 GHz >40 GHz not reported > ~ 100 GHz >30 GHz Spectrum Linewidth nm <0.1 nm 0.2–0.6 nm 1–3 nm <1 nm 1–2 nm Beam divergence (angle)/quality degree symmetric (2–20°)/no astigmatism elliptical (15/40°)/astigmatism Speckle looking high low moderate high Single/multi‐mode behavior looking pure single multi‐transverse quasi‐single/multi‐longitudinal Thermal Wavelength stability (shift) nm/Kelvin 0.06 nm/K 0.3 nm/K 0.3 Reliability (lifetime) hours high high Manufacture Array scaling dimension 2D 1D Wafer diameter inch(mm) 4″ (100 mm) & 6″ (15O mm) ready 4″ (100 mm) to be ready Assembly and packaging complexity simple and easy complex Growth and processing complexity monolithic/standard CMOS regrowth/facet coating needed Cost amount low high

Table 1.4 Attributes of VCSEL in datacom, sensing, and manufacturing.

      Source: [Table by B. D. Padullaparthi and K. Iga] [copyright reserved by authors].

Datacom	Sensing	Manufacturing	Others (Performance)
high fiber coupling efficiency	high peak pulse powers	vertical integration	low threshold currents
high bandwidths	high PCE and SE	array scalability and small footprint	circular beam (Low divergence)
high modulation speed	high rise and fall time (integration time)	easy alignment and packaging	narrow linewidth
low power consumption (energy efficient in data centers)	low power consumption (long battery operating times consumer)	monolithic process handling (epi‐growth and wafer fabrication)	operation in single‐mode and multi‐mode
wavelength tunability (WDM)	high beam quality	low cost and high yield	high reliability (auto grade)
low thermal impedance (efficient heat dissipation)		on‐wafer testing	wavelength stability

Table 1.5 Mode dependent VCSEL applications.

      Source: [Arranged by K. Iga and B. D. Padullaparthi] [copyright reserved by authors].

	Optical Communications	Optical Sensing	Others
Single mode	mid distance transceiver	optical mouse	printers
		gas sensing	displays