High-frequency modulation of oxide-confined verticalcavity surface emitting lasers

Abstract

RF drive frequency from an actively modelocked fibre ring laser without controlling the modulator bias. In general, whenever the RF drive frequency is detuned by an amount equal to fwl2, from the frequency where stable pulses are found, the laser would produce pulses at repetition rate two times the RF drive frequency.Similarly, when detuning is -:fc 4 vf3, then the repetition rate of output pulses can be tripled.

High-efficiency, high-speed VCSELs for optical interconnects

“…Figure 4 plots the relaxation resonance frequency, f res , and 3 dB frequency, f 3 dB , as a function of the square root of the current above threshold. The modulation current efficiency factor (MCEF), defined as f 3 dB / √ (I − I th ), is 16.7 GHz/mA 1/2 , very close to the highest reported value of 16.8 GHz/mA 1/2 for QW-based VCSELs [9]. This high MCEF is mainly due to better lateral mode confinement, consequence of our improved tapered oxide aperture design.…”

Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

“…The time derivative on the left reduces to zero at steady state. The net energy flux due to current injection and leakage is given by (4) where is the QW thickness, and and are the conduction and valence band QW depth, respectively.…”

“…In brief, the thermal rollover behavior is caused by the positive feedback process between raised temperature and reduced power conversion efficiency. In state-of-the-art VCSEL designs, oxide apertures are introduced to achieve better confinements of both current injections and optical modes [2]- [4], and the scalability of such devices has been investigated with respect to threshold current and intrinsic threshold voltage [5]. In VCSELs with small oxide apertures, the self-heating problem becomes more severe due to several factors: the enhanced power density in small device volume, severe Joule heating in distributed Bragg reflector (DBR) stacks, and the oxides that act as electrical and thermal blocking layers.…”

Design, fabrication, and performance of infrared and visible vertical-cavity surface-emitting lasers

“…Monolithic oxide-confined IR VCSEL's now hold several performance records. They include: 1) lowest threshold current of 10 A [7], which is lower than any other diode laser; 2) lowest threshold voltage, 1.33 V at 970 nm [89]; 3) highest power conversion efficiency of 50% [4], which is competitive with the best edge emitters; and 4) highest small-signal modulation bandwidth of 20 GHz [98].…”