KR20010089444A - Diode array side-pumping of a laser system - Google Patents

Abstract

The present invention relates to a radar system, comprising at least one closely spaced diode array (2) spaced apart to emit radiation pump energy and a plurality of waveguides (6) spaced thereon, each waveguide being a diode It emits a laser when exposed to the radiation pump energy emitted from it.

Description

Diode array side-pumping of laser systems {DIODE ARRAY SIDE-PUMPING OF A LASER SYSTEM}

Diode pumped solid-state crystal lasers are increasingly recognized because of their small size and high output characteristics.

In optical signal processing, however, it is necessary to use a pumped waveguide to generate laser power other than solid state crystal lasers, which is more difficult than for example integrated into optical integrated circuits.

Suitable waveguides include, for example, doped cores of optical fibers or doped planar waveguide structures.

Such waveguides, ie waveguides capable of generating laser power when pumped with pump energy, currently require efficient coupling of the pump energy optical signal to the doped core of the optical fiber, for example via optical fiber cladding.

Several coupling techniques have been proposed to minimize coupling losses, but require additional devices / structures that need to be integrated into optical integrated circuits, for example, resulting in designs that are more complex and cannot be miniaturized.

Moreover, typically a separate source of pump energy optical signal is needed for each waveguide to be pumped, which source is individually coupled to each waveguide.

The present invention relates to a diode pumped laser system.

1 shows a first embodiment of the present invention.

2 shows a second embodiment of the present invention.

3 shows a third embodiment of the present invention.

4 shows a fourth embodiment of the present invention.

5 illustrates the use of the present principles in a multi-mode interfering device.

6 shows a further embodiment of the present invention.

According to the present invention, there is provided at least one closely spaced diode array arranged to emit radiation pump energy and a plurality of waveguides spaced therein, the laser being exposed when each waveguide is exposed to radiation pump energy emitted from the diode. There is provided a laser system arranged to emit light.

Thus, a single diode array is used as a single source for pumping multiple waveguides simultaneously without the need for separate coupling means.

The waveguide is arranged to emit a laser at a different frequency. This is possible, for example, by using multiplexed optical signals.

Such a system includes a combiner that combines the laser outputs of the individual waveguides to form a combined laser output.

Such systems further comprise reflecting means spaced close to the waveguide and an array upon reflecting the radiation pump energy emitted from it onto the waveguide.

Many waveguides include optical fiber sets or planar waveguides.

The waveguide forms a multi-mode interference device.

The waveguide can be formed as part of a multi-mode waveguide structure that can be integrated into a single mode waveguide.

Within the scope of the present invention, preferred forms are described below for illustration with reference to the drawings.

In Fig. 1, a first embodiment 1 of the present invention is shown. In this embodiment, an optical fiber set or bundle in the form of a distributed feedback (DFB) fiber laser 2 having a tuned Bragg grating structure is pumped by a diode bar 3 to provide specific frequency characteristics. In this example, 32 DFB lasers are provided. Of course, other arrangements are possible, such as for example, where the optical fibers are close apart and form a monolayer on the diode bar. Obviously, many other arrangements are also possible. The diode bar 3 functions as a high intensity pump that allows the DFB laser to emit a laser. 32 optical fibers are grouped together into one splitter 6 to provide an output 7 with multiple combined frequency channels.

The principle of FIG. 1 is also extendable to other waveguide systems. For example, in FIG. 2, a diode bar 10 is located on the waveguide 17, on which a DFB laser set 12 is formed in the core. Diode bar 10 is used to pump DFB laser 12 to provide an output 13.

Other arrangements as shown in FIG. 3, in which a waveguide 20 is provided on the substrate 21 and a diode bar 22 is provided to pump the waveguide 20, are also possible. The diode bar 22 is inclined with respect to the substrate 21 so that the pumping waveguide energy is reflected by the substrate 21 and then reflected by the reflector 24 to provide enhanced operating characteristics. Pumping allows waveguide 20 to emit a laser to provide output 25.

In FIG. 4, another arrangement is shown in which the diode bar 30 is located at one end of the substrate 31 including the DFB laser set therein. Diode bar 30 is used by DFB laser 32 to emit a laser to provide output 33.

The arrangement of FIGS. 1-4 is a low cost arrangement for pumping multiple waveguides simultaneously. This is particularly desirable when constructing laser devices or other large-scale pumpings of active waveguides. One example of such an application is in the field of multi-mode interfering devices. Such a device is formed on waveguide 40 as shown in FIG. 5 and includes a set of active waveguides 41 between two couplers 42, 43. The diode bar 44 is positioned above the active portion to provide large-scale pumping of the active waveguide 41 and thus to provide multiple output couplings from the input 46 to the output 47 as needed.

Referring to FIG. 6, a further embodiment is shown where large power coupling is required for high power applications. Diode bar 50 is used to provide a high power 53 pump waveguide that can be used to pump other devices by pumping large multi-mode waveguides 51 that are pointed at the ends to become single mode waveguides 52. .

Those skilled in the art will appreciate that various modifications, such as shown in particular embodiments, are outlined without departing from the spirit or scope of the invention. Therefore, the present invention has been described for purposes of illustration and not of limitation.

In the claims and the abstract, the word "comprising" is used in the same sense as "including" except where necessary due to language or necessary implications, ie, the disclosed features relate to further features of the various embodiments of the invention.

Claims (8)

At least one array in close proximity to the diode emitting radiation pump energy; And A plurality of waveguides spaced apart from the array, each of the waveguides emitting a laser when exposed to the radiation pump energy emitted by the diode. The laser system of claim 1, wherein the waveguide emits a laser at a different frequency. 3. The laser system of claim 1 or 2, wherein the system further comprises a combiner for combining the laser outputs from the respective waveguides to form a combined laser output. The system of claim 1, wherein the system further comprises reflecting means for reflecting the radiation pump energy emitted from the array to the waveguide and spaced apart from the waveguide and the array. Laser system. 5. The laser system of claim 1, wherein the plurality of waveguides comprise a set of optical fibers. 6. 6. The laser system of any of claims 1 to 5, wherein the plurality of waveguides comprise a planar waveguide set. 7. The laser system of any of claims 1-6, wherein the waveguide constitutes a multi-mode interference device. 8. The laser system of any of claims 1 to 7, wherein the waveguide is formed as part of a multi-mode waveguide structure that can be integrated into a single mode waveguide.