Active mode locking of double heterostructure lasers in an external cavity
Proton bombarded stripe geometry lasers have been actively mode locked in an external cavity consisting of a lens, a Fabry-Perot etalon, and a mirror. Under optimized conditions, pulses as short as 5.3 psec have been observed from measurement of the second harmonic autocorrelation function. The dependence of the pulse width on external parameters was studied in detail. The pulse width t/sub 1/2/ decreases with increasing direct current. The functional dependence of the pulse width on current indicates that a saturable absorption mechanism is present in the laser which causes significant pulse shortening. The pulse width decreases with increasing rf current. The pulse width is a sensitive function of the frequency detuning of the applied rf current. The shortest pulses are observed when the applied frequency is less than the round trip frequency of the pulse in the cavity. The frequency dependence of the pulse width was obtained using a long cavity with multiple pulses in the cavity. The shortest pulses occur between 0.9 and 1.4 GHz. The Fabry-Perot etalon limits the emission to a 1.9-A spectral band. At optimum mode locking the band is approx.30 A below the peak of the multimode emission obtained without the etalon. The shift of the gain curve to lower enery indicates that additional loss is introduced by the feedback from the external cavity. The experimental results are shown to be in good agreement with a theoretical description of mode locking.
- Research Organization:
- Bell Laboratories, Murray Hill, New Jersey 07974
- OSTI ID:
- 6285052
- Journal Information:
- J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 52:7; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420300* -- Engineering-- Lasers-- (-1989)
ABSORPTION
BARYONS
CORRELATIONS
ELEMENTARY PARTICLES
FABRY-PEROT INTERFEROMETER
FERMIONS
FREQUENCY DEPENDENCE
GEOMETRY
HADRONS
HARMONICS
INTERFEROMETERS
IRRADIATION
LASER CAVITIES
LASERS
LENSES
MATHEMATICS
MEASURING INSTRUMENTS
MIRRORS
MODE LOCKING
NUCLEONS
OPTIMIZATION
OSCILLATIONS
PARAMETRIC ANALYSIS
PROTONS
PULSES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR LASERS
TUNING