External optical resonator for a semiconductor laser
AssigneeSiemens Aktiengesellschaft
InventorGeorg Boeck
Life of this patent
Estimating the term…
Abstract
An external optical resonator for use with a semiconductor laser has a high selectivity and phase steepness for the input reflection factor in the region of the resonance frequency and is highly stable. An optical directional coupler is coupled to the semiconductor laser and two gates of the coupler are connected to one another by a radiation transmission path for externally transmitting radiant power. The coupling factor of the directional coupler is selected such that the radiation coupled into one waveguide of the coupler is nearly completely coupled over to the other waveguide of the coupler. Nearly complete suppression of all secondary modes is obtained by using a wavelength selective directional coupler in place of a broad band directional coupler.
Claims27
An external optical resonator for a semiconductor laser, comprising:
- an optical four-gate coupler having:
- a first gate couplable to the semiconductor laser so that radiant power from said laser that is coupled into said first gate is no more than five percent coupled to a second gate and is at least ninty-five percent coupled to a third gate,
- a fourth gate of said coupler being such that radiant power coupled in through said fourth gate is at least ninty-five percent coupled to said second gate and is no more than five percent coupled to said third gate,
- said second gate being such that radiant power coupled in through said second gate is coupled to said first gate,
- a radiation transmission path connected between said second gate and said fourth gate for transmission of radiant power between said second gate and said fourth gate externally of said coupler, said radiation transmission path being formed by an optical waveguide,
- a feedback device disposed between said second gate and said fourth gate for reflecting a predetermined amount of radiant power coupled out of said second gate and transmitted over the radiation transmission path back into said second gate.
Dependencies are inferred from the claim text.