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Methods of Controlling Turn On of Gain Switched Diode Lasers

IP.com Disclosure Number: IPCOM000107633D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 81K

Publishing Venue

IBM

Related People

Fan, B: AUTHOR [+2]

Abstract

Disclosed is a method to control the turn-on delay of gain-switched semiconductor diode lasers which can generate picosecond light pulses with sub-picosecond pulse-to-pulse timing jitter (1).

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This is the abbreviated version, containing approximately 64% of the total text.

Methods of Controlling Turn On of Gain Switched Diode Lasers

       Disclosed is a method to control the turn-on delay of
gain-switched semiconductor diode lasers which can generate
picosecond light pulses with sub-picosecond pulse-to-pulse timing
jitter (1).

      Fig. 1 shows the light pulses from a gain-switched laser diode
at different dc bias levels as observed on a streaking camera. The
time resolution of the camera is N5 ps. The electrical drive pulses
have a duration of N150 ps (FDHM). Since the operating conditions for
the gain-switched laser are Idc bias <Ithreshold<Ipulse drive, the dc
background light output is insignificant compared with the laser
pulse intensity. In addition, the risetime and duration of the laser
pulses are approximately equal: the duration is 19 - 22 ps (FDHM) and
transition time (30% T 70%) is in the range of 5 - 7 ps. Light
pulses having a fast leading edge are essential for low-skew
optoelectronic conversion (2).  At very high bias levels, secondary
pulses appear.

      It is also observed that the turn-on time of the laser depends
strongly on the dc bias level. Fig. 2 plots the relative time at
which the light pulse intensity reaches a constant level to trigger
the optoelectronic circuits at various bias levels. By increasing the
bias level from 0 to 13 mA, the turn-on delay time of the
gain-switched laser can be reduced monotonically by N90 ps. Continued

      The fine control over the turn-on time of gain-switched...