WIDE-BAND TUNABLE LASER

Abstract

A tunable laser module having two or more tunable lasers exhibiting different, possibly contiguous or partially overlapping wavelength regions. The lasers are integrated into a single package, thereby extending a total wavelength range for the package that is substantially beyond that covered by a single laser while—at the same time—providing gap-free wavelength range coverage. Of further advantage, the laser module employs a locking mechanism that is relatively immune from backscatter.

Description

BRIEF DESCRIPTION OF THE DRAWING

A more complete understanding of the present invention may be realized by reference to the accompanying drawing in which:

FIG. 1 is a schematic block diagram of a hybrid packaging of a commercially available laser module illustrative of the Prior Art;

FIG. 2 is a schematic block diagram of a first embodiment of a wide-band tunable laser package according to the present invention;

FIG. 3 is a schematic block diagram of an alternative embodiment of a wide band tunable laser package according to the present invention;

FIG. 4 is a schematic block diagram of a wide-band tunable laser package according to the present invention illustrating lock sharing;

FIG. 5( a) is a schematic block diagram of an additional alternative embodiment of a wideband tunable laser package according to the present invention illustrating driving circuitry sharing;

FIG. 5( b) is a schematic block diagram of an additional alternative embodiment of the wideband tunable laser package of FIG. 5(a) illustrating an off-axis wavelength locking arrangement thereby eliminating problems associated with back-reflections; and

FIG. 6 is a block diagram of a frequency locking mechanism according to the present invention.

Claims

1. A laser module comprising: two or more lasers for generating laser light;a set of optical components for operating upon the generated laser light prior to its output; anda locker, for monitoring and locking the characteristics of the laser light to be output;CHARACTERIZED IN THAT:the locker is shared between the two or more lasers.

2. The laser module of claim 1: FURTHER CHARACTERIZED IN THAT:the locker is not in a direct optical path of the laser light to be output.

3. The laser module of claim 1, wherein said locker comprises: a splitter, for splitting the generated laser light and directing it into two or more distinct optical paths;an etalon positioned in one of the distinct optical paths;a photodetector, positioned in the optical path containing the etalon, for monitoring the wavelength of the generated laser light;anda second photodetector, positioned in another optical path, for monitoring the power of the generated laser light.

4. The laser module of claim 3, further comprising a switch/combiner for switching/combining the generated laser light into a single output.

5. The laser module of claim 4 wherein said switch/combiner comprises a Mach-Zehnder Interferometer switch.

6. The laser module of claim 5 wherein said locker is positioned in an optical path optically coupled to a particular path of the switch/combiner, and an output of the module is within a different optical path of the switch/combiner such that the switch/combiner may selectively switch generated laser light between the locker and the output, as desired.

7. The laser module of claim 6 further comprising an integrated planar lightwave circuit (PLC), said PLC including: the locker; andan integrated coupler/switch for selectively coupling/switching the generated laser light between the locker and an output as desired.

8. The laser module of claim 7 wherein the PLC is an InP device.

9. The laser module of claim 8 wherein the integrated frequency filter includes a Mach-Zehnder filter.

10. The laser module of claim 9 further comprising one or more lenses, positioned in an optical path between the PLC and an output of the module.

11. The laser module of claim 10 further comprising common driving electrical circuitry, shared among the two or more lasers.