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550 mW 980 nm Laser Diode Module for EDFA (FOL 0909 series)

Accompanied by the increase in transmission capacity ofbackbone systems and metropolitan networks caused by
the expansion of FTTH, erbium-doped fiber amplifier(EDFA) is playing an important role in a wavelength division multiplexing (WDM) system. For pumping sources ofEDFA, laser modules (LDMs) of 1480 nm band and 980
nm band are used. 980 nm LDM, which has advantages oflow noise and low power consumption, has conventionallybeen used as a preamplifier which needs relatively lower
pumping power. Recently, 980 nm LDM becomes morereliable and has higher output power. A progress in 980
nm LDM enables such EDFA that uses a 980 nm LDM
only, instead of using 1480 nm LDMs as a booster amplifier. This type of EDFA is becoming mainstream because ofits features such as low power consumption, low price andspace-saving. High output power of more than 500 mW isrequired in order to obtain EDFA gain using only one 980
nm LDM. Moreover, to adjust EDFA gain in accordancewith the change of WDM count, a stable operation over awide output power range is required.
Furukawa Electric has been producing 980 nm LDM
with operating power up to 450 mW. A 550 mW 980 nm
LDM (Figure 1), suitable for recent EDFA designs, hasbeen newly developed and commercialized.

the output power rollover by heat generation, the coupling
efficiency between the LD chip and the optical fiber andso on.
In our 980 nm LD chip, the optical density at the active
layer is lowered and, as a result, the suppression of theoptical damage and the high reliability are achieved.
As a consequence of reducing the forward voltage, thesuppression of the heat generation and the advancementof the thermal rollover point were realized. And theincrease of the power consumption caused by higher
operating power was designed to the minimum. In addition, the module design was also reviewed. By optimizing
the mode field matching between the LD chip and theoptical fiber, the coupling efficiency was improved and thehigh kink-free power was achieved. A light-current (I -L )and a voltage-current (I -V ) characteristics of the 550 mW
LDM are shown in Figure 2.

800

5.07004.5
4.0600I-L

3.55003.0400I-V3002.5
2.0
1.52001.0100

LD forward voltage（V）

INTRODUCTION

Fiber output power（mW）

1.

0.500200

400

600

0.0800 1000 1200 1400

LD forward current（mA）

Figure 2

Figure 12.
2.1

980 nm pump laser module.

FEATURESHigh output power by electrical and opticaldesignA maximum operating power of LDM is determined byvarious factors such as the optical damage of a LD facet,

I -L and I -V curve.

2.2Stabilization of output power by optimizing FBG
parameters
Generally, fiber bragg grating (FBG) is used in order tostabilize the lasing wavelength of LDM. There is, however,a well known problem that the oscillation state of the laser
becomes unstable due to the interaction between the LD
chip and the reflected light from FBG, thereby the lasing
wavelength or/and the output power fluctuate over time.

Furukawa Review, No. 37

2010

1

550 mW 980 nm Laser Diode Module for EDFA (FOL 0909 series)

When the number of WDM channels is several, required
980 nm pump power is a couple of dozen mW. In such alower power range, the suppression of fluctuation
becomes more difficult. The newly developed LDM exhibits stable spectrum over a wide power range due to theoptimization of the FBG parameters (Figure 3). Also, thepower fluctuation is well stabilized to lower than 0.5% athigh power range (-550 mW) and lower than 2% at lowpower range (30 mW-) (Figure 4).

3.

CONCLUSION

The high power 980 nm LDM has been developed as anEDFA pumping source and fiber output power of 550 mW
has been realized. In addition, the fluctuation of the output power is suppressed over a wide operating powerrange. Therefore this product can fully meet your needs
as a pumping source for high performance EDFAs.
For more information, please contact
Global Business Solutions, Telecommunications Company
Tel: +81-3-3286-3253 Fax: +81-3-3286-3978

60
Fluctuation（%）

40
Intensity（dB）

3

Pf =30 mW
Pf =300 mW
Pf =550 mW

200

Pf ＝30 mW

210∆ ＝1.1%−1−2-20−3-4001020304050

60708090 100Time（sec）-60970972974976

978Figure 4Wavelength（nm）

Figure 3

Power stability vs time.

Output spectrum.
Table 1

Performance specifications.
Ts=25°C

Parameters
Output power
FOL0909A46
FOL0909A47
FOL0909A48
FOL0909A49
FOL0909A50
FOL0909A51
FOL0909A52
FOL0909A53
FOL0909A54
FOL0909A55
LD Threshold Current

Sym.

Min.

Typ.

Max.

Ith460
470
480
490
500
510
520
530
540
550
－－－－－－－－－－－
70－－－－－－－－－－
85

Peak Wavelength

λc

λ－1

λ

λ＋1nm

Peak， Pf=Rated Power
λ=974 nm～976 nm

ΔλVf
If (EOL)
Pkink
Ikink－－－－=<1.1 x If (BOL) max.
=1.1 x Rated Power=1.15 x If (BOL)

22.5nmVmAmWmA

FWHM， Pf=Rated Power
Pf=Rated PowerEnd of Life－－Pf Stability

Pstb

－－

2.0%

Pf=30 mW～Rated power，60 sec， peak topeak，Fiber pigtail is fixed

Monitor Responsivity

Im/Pf2－

20mA/mW

Monitor Dark Current
TEC Current
TEC Voltage

Id
Itec
Vtec－－－－－－

100
1.5
3.5

nAAV

Tracking Error

T.E.

－0.5－

0.5dB

Thermistor Resistance
Thermistor B constant

RthBth9.5－103900

10.5－kΩK

Spectral Width
LD Forward Voltage
LD Forward Current (EOL)
Kink Free Power
Kink Free Current

Pf

UnitmWmACondition
If (BOL)=<890 mA
If (BOL)=<910 mA
If (BOL)=<930 mA
If (BOL)=<950 mA
If (BOL)=<970 mA
If (BOL)=<990 mA
If (BOL)=<1010 mA
If (BOL)=<1030 mA
If (BOL)=<1050 mA
If (BOL)=<1070 mA
CW

VrPD=5 V，average Pf=0 mW～Rated PowerVrPD=5 V
If (EOL)， ΔT=50℃
If (EOL)， ΔT=50℃
Pf/Im
Tc=－20～75℃， referred to @25℃
Ts=25℃
Ts=25℃

Furukawa Review, No. 37

20102