NewNew Products
Products

1480-nm Cascaded Raman Laser with 50-W Output PowerThe Erbium-doped fiber amplifier (EDFA) which is commonly used for long-distance optical communication system is capable of amplifying the light signal at high quality
and at high efficiency. These features can be achieved
effectively by sending a single-mode pumping light into
the amplifier which consists of a single-mode fiber. If thesignal amplified in the EDFA is a pulse with very shortpulse width, as compared with the case of a continuouswave, higher power pumping light is required. We havecommercialized a Cascaded Raman Laser of high output
pumping laser used in an amplifier for a femtosecond
pulsed laser. With this Cascaded Raman Laser, higher
than 50W of 1480nm-band output light is gained from thesingle-mode fiber and it can be made available for a highoutput power to all EDFA, not only for a femtosecond
pulse.

2.

BACKGROUND OF THE DEVELOPMENTDESCRIPTION OF THE PRODUCTFigure 2 shows the configuration drawing and Figure 3shows the mechanical dimensions of the product. Thisproduct consists of an output light of ytterbium (Yb) fiber
laser oscillating at 1117 nm sent into a cascaded Raman
resonator and then oscillated at 1480 nm as the fifth-orderof Raman scattering light. The example of the output light
spectrum of this product is shown in Figure 4. Pumping
light of approx. 150 W is sent into the Yb fiber laser and1117 nm light of higher than 120 W as maximum outputs.
Considering this signal as a fundamental wave and making Raman shift on it, a cascaded Raman laser output ofhigher than 60 W is available. This product has the spectrum characteristic shown in Figure 4 and the light power
at 1480 nm-band accounts for 70-90 percent of the total
output power of this product. Power characteristics of
total output power and output power at 1480 nm-band of
this product are shown in Figure 5. In that figure, you can
see that this product achieves higher than 50 W at the1480 nm-band output power.

Yb fiberHR

Raman laser
outputOC

Cascaded Raman OutputPD
monitorresonator

1117 nm Yb fiber

Figure 2 Configuration drawing.

29560

φ405

387

20OFS Fitel, LLC, a company of our group, has a trackrecord in research, development and commercialization ofCascaded Raman Lasers since the 1990s and now is oneof the few companies which sell fiber bragg gratings (FBG)
for Cascaded Raman Lasers and fiber for Raman resonators. In undertaking joint research and development withOFS, we have made presentations in conferences, andsold test models of a 40 W output products and mass production models of 20 W output. This time, in response tocustomers in the US, we have advanced the developmentof a mass production model for the product of a 50 W output (Figure 1) in cooperation: optical design and reliability
validation at OFS Laboratories, and chassis, control board
and packaging design at Furukawa Electric.

3.

16INTRODUCTION

17

1.

1163.5

61.4

Figure 1 External view of this product.

Figure 3 Mechanical dimensions.

Furukawa Review, No. 43

2013

49

1480-nm Cascaded Raman Laser with 50-W Output Power

Table 1

Specifications of this product.

Specifications.
Unit

Min.

Intensity [a.u.]

Oscillation mode

Max.
c.w.

Polarization

Random1480 nm-band output50 W

Output power variable range%10100

1480 nm-band center wavelength

nm147814821480 nm-band wavelength linewidthnm

6

Environmental conditions.
1000

1100

1200

1300

1400

1500

1600

Wavelength [nm]Figure 4 Example of output spectrum.

70Min.

Max.

℃

-2070

Storage environmental humidity

%

2085

Operating environmental
temperature

℃

1040

Operating environmental humidity

%

2085

Supply voltage

DCV

33401480nm-band60
Light output power [W]Unit
Storage environmental temperature

Full band

For more information, please contact:
Administrative Department,
Telecommunications Company
Tel: +81-3-3286-3768 Fax: +81-3-3286-3708
E-mail: fiberlaser_bsgr@furukawa.co.jp

50403020100036912Driving current of pumping LD [A]Figure 5 Output power in total and 1480 nm-band.

4.

CONCLUSIONAs the pumping light source used in an EDFA for a femtosecond pulsed laser, we have commercialized high output power Cascaded Raman Laser with higher than 50 W
at 1480 nm-band, made by joint development with OFS.
As a summary of this product, we illustrate the key specifications and environmental conditions in Table 1.

Furukawa Review, No. 43201350