Title :
Limitations of a threshold-sensing scheme for lasers at high bit rates
Author :
Hakki, B.W. ; Bosch, F.
Author_Institution :
AT&T Bell Lab., Allentown, PA, USA
Abstract :
Results for a threshold-sensing method for lasers operating in the gigabit-per-second (GB/s) range are reported. Laser threshold sensing is accomplished by applying a low-frequency (1-20 kHz) dither current at low amplitude (1-2 mA) to the off-state of a laser that is being modulated at normal transmission rate. It is found that acceptable discrimination of the lasing threshold condition is possible for bit rates up to about 2 Gb/s. Loss in threshold discrimination at higher bit rates is attributed to the increased contribution of lasing delay time to the sensing signal when the bias is below threshold.<>
Keywords :
laser beams; laser variables measurement; 1 to 2 mA; 1 to 20 kHz; 2 Gbit/s; bias; lasing delay time; lasing threshold condition; low frequency dither current; normal transmission rate; off-state; sensing signal; threshold discrimination; threshold-sensing scheme; Amplitude modulation; Bit rate; Circuits; Control systems; Delay effects; Frequency; Optical control; Optical modulation; Pulse width modulation; Space vector pulse width modulation;
Journal_Title :
Photonics Technology Letters, IEEE
