Mode-locked semiconductor laser with tunable external cavity
AssigneeHughes Aircraft Company
InventorLuis Figueroa
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Abstract
A mode-locked gallium arsenide crystal laser has a cavity length equal to one-half its principal noise resonance wavelength and an electrode overlying a portion of the crystal, the remaining portion being a self-aligned region diffused or implanted with impurities comprising saturable absorbing centers. An anti-reflective coating is placed on a crystal facet facing an external mirror defining one end of the laser cavity. The resulting laser has improved power, frequency and temporal stability.
Claims17
A semiconductor crystal laser having a very high pulse repetition rate, comprising:
- a semiconductor hole source layer and a semiconductor electron source layer overlying said substrate;
- a semiconductor optical layer sandwiched between said hole source and electron source layers, said optical layer having a principal noise resonance frequency f.sub.0, said optical layer being defined by a near facet and a far facet facing one another;
- electrode means for applying an electric field across said optical layer;
- and
- an external mirror facing said near facet and defining a laser cavity between said mirror and said far facet, said mirror being located such that the length L of said laser cavity is equal to C/2mf.sub.0, where C is approximately the speed of light and m is an integer;
- an electrode of said electrode means partially overlying said electron source, hole source and optical layers so as to cover a partial region of said optical layer;
- and dopant substrate absorbing centers deposited in a remaining region of said optical layer, said remaining region of said optical layer being registered with said electrode.
A gallium arsenide laser capable of mode-locking at a very high repetition rate with improved temporal stability, comprising:
- a gallium arsenide substrate;
- a p-type conductivity gallium arsenide hole source layer and an n-type conductivity gallium arsenide electron source layer overlying said substrate;
- a gallium arsenide optical layer sandwiched between said hole source and electron source layers, said optical layer comprising a self-pulsing laser cavity having a principal noise resonance frequency f.sub.0, said optical layer being bounded by a near facet and a far facet;
- an electrode partially overlying said hole source, electron source and optical layers so as to cover a partial region of said optical layer;
- zinc dopant impurities residing in a remaining portion of said optical layer, said remaining region of said optical layer being in at least approximate registration with said electrode;
- and
- an external mirror facing said near facet and defining a mode locking laser cavity between said mirror and said far facet, said mirror being located such that the length L of said mode locking laser cavity is equal to C/2mf.sub.0, where C is approximately the speed of light and m is an integer.
A method for making a self-aligned semiconductor crystal laser including a semiconductor optical layer having a top boundary, comprising:
- forming an electrode over said top boundary overlying only a first portion of said optical layer;
- depositing saturable absorbing centers through said top boundary into the remaining portion of said optical region in the presence of said electrode.
The method of claim 12 wherein said depositing step comprises diffusing dopant impurities into said optical layer.
Dependencies are inferred from the claim text.