Corning O.t.i. Spa

Corning O.t.i. S.r.l.

Stefano Balsamo

Giorgio Ghislotti

Salvatore Morasca

Fiorenzo Trezzi

Alberto Ferrari

A semiconductor ridge laser for coupling to a single-mode optical fiber has a ridge with a narrow parallel region, a diverging region, and then a wide parallel region that is adjacent to an output facet. A pump region for the laser may be less than the entire area of the ridge and have a &ldquo;T&rdquo; shape. Preferably, the ridge has a depth of about 350 to 550 nm and the narrow parallel region has a length of more than 0.4 times the overall length of the ridge. The wide parallel region at the output enables the laser to obtain low thermal resistance, which leads to a low operating temperature, a low power density in the laser cavity, and low astigmatism.

Semiconductor laser element having a diverging region

A bidirectionally pumped optical amplifier comprises an active fibre having two ends, a first WDM coupler and a second WDM coupler coupled to said ends, a first pump branch coupled to said first WDM coupler comprising a first laser and a grating, for introducing pump radiation in said active fibre in a first direction, and a second pump branch coupled to said second WDM coupler comprising a second laser, for introducing pump radiation in said active fibre in a second direction, opposite to said first direction. A portion of unabsorbed pump residual propagating in the first direction is coupled in one of the two pump branches towards the pump laser included in the pump branch, and locks the emission wavelength of the pump laser. The other pump branch preferably comprises an optical isolator for the pump radiation. Preferably, the pump lasers emit in the 980 nm window.

Optical amplifier with two directional pumping

A bidirectionally pumped optical amplifier ( ) comprises an active fibre ( ), a first WDM coupler ( ) and a second WDM coupler ( ), a first pump: branch ( ) coupled to said first WDM coupler ( ) comprising a first laser ( ) and a first grating ( ), for introducing pump radiation into said active fibre ( ) in a first direction, a second pump branch ( ) coupled to said second WDM coupler ( ) comprising a second laser ( ) and a second grating ( ), for introducing pump radiation into said active fibre ( ) in a second direction, opposite to said first direction. The second laser has an output power P . A first pump residual, having a power P , is coupled into said second pump branch ( ) from the active fibre ( ) and injected into said second laser ( ). The first pump branch ( ) further comprises an optical isolator ( ) for the pump radiation. The output power of the injected laser and the injected pump power residual are such that P /P >2.

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Cairo Montenotte, Italy

Stefano Balsamo