Compact laser source with wavelength stabilized output
A compact, wavelength-stabilized laser source is provided by utilizing a specialty gain element (i.e., formed to include a curved waveguide topology), where a separate wavelength stabilization component (for example, a fiber Bragg grating (FBG)) is used one of the mirrors for the laser cavity. That is, the FBG takes the place of the physical “front facet” of the gain element, and functions to define the laser cavity in the first instance, while also utilizing the grating structure to impart the desired wavelength stability to the output from the packaged laser source. As a result, the FBG is disposed within the same package used to house the gain element and provides a wavelength-stabilized laser source in a compact form.
1. A small form-factor, wavelength-stabilized packaged laser comprising
a housing formed in compliance with small form-factor requirements;
a submount disposed within the housing;
a specialty gain element disposed on the submount, the specialty gain element including a curved optical waveguide configured such that a front facet is non-parallel with a rear facet, the rear facet defining a first mirror of a laser cavity along an optical axis through the curved optical waveguide, the specialty gain element energized to generate optical radiation;
a partially-reflective wavelength stabilization component disposed in close proximity to the front facet of the specialty semiconductor gain element and positioned in optical alignment with the rear facet to form a second mirror of the laser cavity, and also functioning as an optical filter to stabilize the output wavelength of the generated optical radiation; and
an optical output fiber coupled at an endface termination to the specialty gain element and disposed to exit through a sidewall aperture of the housing, the endface termination of the optical output fiber attached to the submount at a first fixing point and affixed within the sidewall aperture at a second fixing point, defining a section of optical output fiber disposed within the small form factor package between the first and second fixing points.
2. The small form-factor, wavelength-stabilized packaged laser as defined in claim 1 wherein the partially-reflective, wavelength-selective filtering component comprises a fiber Bragg grating (FBG) formed in a portion of the section of output optical fiber in close proximity to the front facet of the specialty gain element between the first and second fixing points.
3. The small form-factor, wavelength-stabilized packaged laser as defined in claim 2 wherein the FBG is disposed within a distance no greater than 4 mm from the front facet.
4. The small form-factor, wavelength-stabilized packaged laser as defined in claim 1 wherein the section of optical output fiber within the package is formed to have a length sufficient to include a slight bend between the first and second fixing points for accommodating changes in stress.
5. The small form-factor, wavelength-stabilized packaged laser as defined in claim 1 wherein the wavelength-selective filtering component comprises a discrete component volume Bragg grating (VBG) disposed at a predetermined location on the submount so as form the second laser cavity mirror in alignment with the rear facet of the specialty gain element.
6. The small form-factor, wavelength-stabilized packaged laser as defined in claim 1 wherein the packaged laser further comprises
an incoming optical fiber supporting the propagating of a signal at a predetermined wavelength; and
a wavelength division multiplexer disposed on the submount and aligned with the incoming optical fiber and output optical fiber such that the incoming signal is re-directed into the output optical fiber to co-propagating with the wavelength-stabilized laser output.
7. The small form-factor, wavelength-stabilized packaged laser as defined in claim 6 wherein the packaged laser generates a pump beam at a stabilized output wavelength, providing both an optical signal and related, stabilized pump beam as outputs for use by an optical amplifier.