Small Packaged Tunable Laser

1 . A small, packaged tunable laser comprising:

a rectangular housing having a volume of less than 0.6 cubic centimeters, with six planar exterior walls including a bottom, a top, opposing first and second ends, and opposing sidewalls, the exterior walls forming a hermetically sealed interior space that includes a major axis that extends through the first and second ends;

an electrical input interface positioned on the exterior of the housing and configured to receive an information-containing electrical signal;

an optical output interface positioned at the second end of the housing and aligned with the major axis, the optical output interface configured to transmit a continuous wave optical beam;

a tunable semiconductor laser positioned in the interior space and operable to emit a laser beam having a selectable wavelength; and

a focusing lens assembly positioned in the interior space along an optical path of the laser beam to operatively couple the laser beam to the optical output interface.

2 . The tunable laser of claim 1 , wherein the electrical input interface includes at least one flexible cable that extends outward from the housing.

3 . The tunable laser of claim 1 , wherein the optical path is aligned along the major axis.

4 . The tunable laser of claim 1 , further comprising coupling optics positioned in the interior space along the optical path between the semiconductor laser and the focusing lens assembly, the coupling optics including a pair of coupling lenses and an isolator.

5 . The tunable laser of claim 4 , further comprising a photodiode disposed between the coupling optics and the optical output interface.

6 . The tunable laser of claim 1 , wherein the semiconductor laser is an external cavity tunable laser that includes a tunable filter.

7 . The tunable laser of claim 6 , further including a cavity length actuator to adjust and lock an optical pathlength of the external cavity tunable laser.

8 . The tunable laser of claim 4 , further including a thermoelectric cooler positioned within the interior space between the bottom of the housing and at least one of the tunable semiconductor laser and the coupling optics.

9 . A small, packaged tunable laser comprising:

a rectangular housing with six planar sides including a bottom, top, first end, second end, and two opposing sidewalls, the housing including a hermetically sealed interior space with a length measured between the first and second ends and a width measured between the opposing sidewalls, the length being larger than the width;

laser components positioned in the interior space and including coupling optics and an external cavity laser with a tunable filter, the laser components aligned within the interior space with an optical path of a laser beam that emanates at the external cavity laser and extends along the coupling optics substantially perpendicular to the first and second ends and along a portion of the length of the housing;

an electrical input interface positioned at the first end of the housing and configured to receive an information-containing electrical signal; and

an optical output interface positioned at the second end of the housing and configured to transmit a continuous wave optical signal.

10 . The tunable laser of claim 9 , further including a thermoelectric cooler positioned within the interior space between the bottom of the housing and the laser components.

11 . The tunable laser of claim 9 , wherein the external cavity laser further includes a cavity length actuator to adjust an optical pathlength of the external cavity tunable laser.

12 . The tunable laser of claim 9 , further comprising a focusing lens assembly positioned in the interior space along the optical path to operatively couple the laser beam to the optical output interface.

13 . The tunable laser of claim 12 , wherein the coupling optics are positioned in the interior space along the optical path between the external cavity laser and the focusing lens assembly, the coupling optics including a pair of coupling lenses and an isolator.

14 . The tunable laser of claim 13 , further comprising a photodiode disposed between the coupling optics and the optical output interface.

15 . The tunable laser of claim 9 , wherein the housing has a volume of about 0.55 cubic centimeters.