High-speed large-signal digital modulation of three-terminal low-threshold strained InGaAs/GaAs lasers

1994 ◽  
Vol 6 (6) ◽  
pp. 687-689 ◽  
Author(s):  
S. Siala ◽  
Hanmin Zhao ◽  
M. Govindarajan ◽  
R.N. Nottenburg ◽  
P.D. Dapkus
Keyword(s):  
High Speed ◽  
Large Signal ◽  
Digital Modulation ◽  
Low Threshold

Rapid ankle extension during paw shakes: selective recruitment of fast ankle extensors

1980 ◽  
Vol 43 (3) ◽  
pp. 612-620 ◽  
Author(s):  
J. L. Smith ◽  
B. Betts ◽  
V. R. Edgerton ◽  
R. F. Zernicke
Keyword(s):  
Ankle Joint ◽  
High Speed ◽  
Joint Kinematics ◽  
Time Constraints ◽  
Lateral Gastrocnemius ◽  
Peak Displacement ◽  
Cyclic Movements ◽  
Flexion Extension ◽  
Low Threshold

1. Electromyographic (EMG) signals from slow (soleus) and fast (lateral gastrocnemius) ankle extensors of six cats were recorded during rapid and alternate flexion-extension of the hindlimb elicited by placing the paw in water or by sticking tape to the plantar pads. High-speed 16-mm film, taken at 100 or 200 frames/s, was analyzed to determine the knee and ankle joint kinematics. 2. During 77 typical records, which averaged eight paw shakes each, a single extension-flexion cycle measured by the paw shake interval (PSI) of the electromyogram record, averaged 88 ms and ranged from 55 to 110 ms. LG EMG bursts of 10 ms in duration were synchronized with the peak displacement of ankle flexion. The SOL was inactive throughout these typical records. 3. During four atypical records from one cat, the average OSI was 141 ms, and both lateral gastrocnemius (LG and soleus (SOL) were active simultaneously. At a range of 6--8 cycles/s, these slower shakes are comparable to rhythmic actions of scratching )12) and locomotion (27); cyclic movements that typically include the recruitment of soleus. 4. It is suggested that paw shaking is an automatic movement triggered primarily by large, low-threshold afferents innervating the central plantar pads, which may selectively recruit the fast extensors while inhibiting the slow extensor. This is the only movement of the hindlimb recorded to date in our laboratory in which the tlg was active without the SOL. This unique dissociation of recruitment of slow and fast ankle extensors may be dictated by the time constraints imposed by the rapid cyclic movements of paw shaking.

Microwave-assisted high-speed modulation of semiconductor lasers

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1057-1063 ◽  
Author(s):  
Chung Y. Wu ◽  
Chang Z. Guo ◽  
J. M. Xu
Keyword(s):  
Semiconductor Lasers ◽  
High Speed ◽  
Optical Gain ◽  
Large Signal ◽  
Microwave Assisted ◽  
Active Layers ◽  
Gain Variation ◽  
Speed Modulation ◽  
Signal Simulation ◽  
High Speed Modulation

The electron temperature in the active layers of a semiconductor laser can be raised higher than that of the lattice by an externally applied microwave field. This results in a reduction in the optical gain and forms the basis of laser modulation by microwave heating. The gain variation under electron gas heating is calculated. A complete small signal analysis of current modulation, electron heating modulation, and combined or microwave-assisted modulation of semiconductor lasers is presented. In addition, the sensitivities of the electron and photon responses among the three modulation schemes are compared. Some large signal simulation results of high-speed digital modulation are also included.

Small-signal and large-signal performance test of high-speed optoelectronics devices

2005 ◽  
Author(s):  
N. H. Zhu ◽  
C. Chen ◽  
J. W. Sun ◽  
E. Y. Pun ◽  
P.S. S. Chung
Keyword(s):  
High Speed ◽  
Performance Test ◽  
Small Signal ◽  
Large Signal ◽  
Optoelectronics Devices
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