US 6,665,320 B1 · Wideband tunable laser sources with multiple gain elements

Abstract

This invention provides a tunable laser in which a plurality of gain elements (e.g., semiconductor diodes) with a plurality of gain spectra are optically coupled to a splitting-combining means (e.g., a wavelength router or fiber-optic coupler) in parallel, and the splitting-combining means is in optical communication with a wavelength-selecting means (e.g., a diffraction grating optically coupled to a movable mirror). The tunable laser of the present invention further comprising an optical fiber, optically coupling the splitting-combining means to the wavelength-selecting means. The use of a plurality of distinct gain spectra greatly enhances the tuning range of the tunable laser in the present invention. Moreover, by employing a long optical fiber as a substantial portion of an external cavity, the axial-mode spacing in the laser cavity is so small that mode-hops are effectively inconsequential for practical purposes, thereby rendering the wavelength tuning to be effectively continuous in the tunable laser of the present invention. Additionally, the availability of a plurality of the gain spectra can be further exploited, so as to provide additional capabilities in wavelength selecting/tuning. As such, the present invention provides a versatile and robust tunable laser in a simple and low cost construction.

Claims51

Dependent claims

A tunable laser comprising:

a. a plurality of gain elements having a plurality of gain spectra, wherein at least two of said gain spectra are distinct;
b. a wavelength-selecting means for selecting a distinct wavelength;
c. a splitting-combining means on one side in separate optical communication with each of said gain elements and on the other side in optical communication with said wavelength-selecting means such that a first beam propagating away of any of said gain elements is directed towards said wavelength selecting means and such that a second beam received from said wavelength selecting means with said distinct wavelength is directed to a corresponding gain element of said plurality of gain elements, said corresponding gain element having a gain spectrum at least partially overlapping said distinct wavelength;
d. at least one mode hops reducing means providing optical communication between said wavelength-selecting means and said splitting-combining means for providing an axial-mode spacing such that at least one of said first beam and said second beam has mode hops sufficiently smaller than a required tuning resolution, said reducing means selected from a group consisting of an axial-mode control means and an axial-mode structure;
and
wherein said reducing means is operated in correspondence with said wavelength-selecting means such that a tuning range is spanning up to said at least two distinct gain spectra.

3 more elements

Dependencies are inferred from the claim text.

Wideband tunable laser sources with multiple gain elements

Life of this patent

Wideband tunable laser sources with multiple gain elements

Life of this patent

Abstract

Claims51