AGERE D2570H912, D2570H911, D2570H910, D2570H909, D2570H908 Datasheet

Data Sheet, Rev. 3

July 2001

D2570, D2526, D2555 Wavelength-Selected

Direct Modulated Isolated DFB Laser Module

The 1.5 μm D2570, D2526G, and D2555 Laser Modules are available in a 14-pin, hermetic, butterfly package.

Features

■ITU wavelengths available from 1528.77 nm —1610.06 nm

■SONET/SDH compatible up to OC-48/STM-16

■Temperature tunable for precise wavelength selection

■Integrated optical isolator

■High-performance, multiquantum well (MQW) distributed-feedback (DFB) laser

■Industry-standard, 14-pin butterfly package

■Characterized at 2.488 Gbits/s (NRZ)

■InGaAs, PIN photodetector back-facet monitor

■Low threshold current

■High-reliability, hermetic packaging

■Excellent long-term wavelength stability can eliminate the need for external wavelength locker

■Qualified to meet the intent of Telcordia Technologies * 468

*Telcordia Technologies is a trademark of Telcordia Technologies, Inc.

Applications

■Three direct-modulated DWDM families available to meet a number of OC-48/STM-16 applications:

—Extended reach (100 km)

—Very long reach (170 km)

—Metro DWDM

—Digital video

Product Codes

Product	Peak	Dispersion
Code	Power	Performance
D2570H	10 mW	1800 ps/nm (100 km)
D2526G	2 mW	1800 ps/nm (100 km)
D2555G	2 mW	3000 ps/nm (170 km)

Description

The Direct Modulated Isolated DFB Laser Module contains an internally cooled, InGaAs, MQW, distrib- uted-feedback (DFB) laser designed for 1.5 μm applications. The following three direct-modulation DWDM product families have been established to meet various OC-48/STM-16 system applications:

■D2526-type: designed to be used in OC-48/ STM-16 (2.488 Gbits/s) for extended reach, dense WDM applications (1800 ps/nm). The wavelength of the laser can be temperature-tuned for precise wavelength selection by adjusting the temperature of the internal thermoelectric cooler.

■D2555-type: high-performance device designed for very low dispersion; used in fiber spans exceeding 170 km (3000 ps/nm).

■D2570-type: high-power, direct-modulated laser eliminates the need for optical amplifiers in DWDM many applications.

D2570, D2526G, D2555 Wavelength-Selected	Data Sheet, Rev. 3
Direct Modulated Isolated DFB Laser Module	July 2001

Description (continued)

Controlled Feedback

The module contains an internal optical isolator that suppresses optical feedback in laser-based, fiber-optic systems. Light reflected back to the laser is attenuated a minimum of 30 dB.

Controlled Temperature

An integral thermoelectric cooler (TEC) provides stable thermal characteristics. The TEC allows for heating and cooling of the laser chip to maintain a temperature of 25 °C for case temperatures from –40 °C to +70 °C. The laser temperature is monitored by the internal thermistor, which can be used with external circuitry to control the laser chip temperature.

Controlled Power

An internal, InGaAs, PIN photodiode functions as the back-facet monitor. The photodiode monitors emission from the rear facet of the laser and, when used in conjunction with control circuitry, can control optical power launched into the fiber. Normally, this configuration is used in a feedback arrangement to maintain consistent laser output power.

Standard Package

The laser module is fabricated in a 14-pin, hermetic, metal/ceramic butterfly package that incorporates a bias tee, which separates the dc-bias path from the RF input. The RF input has a nominal 25 Ω impedance.

The laser module is equipped with SMF-28 * type fiber. The fiber has a 900 µm tight buffer jacket. Various connectors and pigtail lengths are available.

Agere Systems’ optoelectronic components are being qualified to rigorous internal standards that are consistent with Telcordia Technologies TR-NWT-000468. All design and manufacturing operations are ISO * 9001 certified. The module is being fully qualified for central office applications.

*ISO is a registered trademark of The International Organization for Standardization.

†SMF-28 is a trademark of Corning Inc.

Pin Information

Pin	Name
1	Thermistor
2	Thermistor
3	Laser dc Bias (Cathode) (–)
4	Back-facet Monitor Anode (–)
5	Back-facet Monitor Cathode (+)
6	Thermoelectric Cooler (+)*
7	Thermoelectric Cooler (–)†
8	Case Ground
9	Case Ground
10	Case Ground
11	Laser Anode (+)†
12	RF Laser Input Cathode (–)
13	Laser Anode (+)†
14	Case Ground

*A positive current through the thermoelectric heat pump cools the laser.

† Both leads should be grounded for optimum performance.

7	6		5		4			3		2		1
–				+			–		–
		+
							L1						TH
	TEC						160 nH
												10 kΩ

				R1	ISOLATOR
					Ω
	PACKAGE			20
	GROUNDS					NC
			+	–	+
8	9	10	11	12	13	14	1-567F.b

Top view.

Figure 1. Circuit Schematic

2	Agere Systems Inc.

Data Sheet, Rev. 3	D2570, D2526G, D2555 Wavelength-Selected
July 2001	Direct Modulated Isolated DFB Laser Module

Absolute Maximum Ratings

Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess of those given in the performance characteristics of the data sheet. Exposure to absolute maximum ratings for extended periods can adversely affect device reliability.

Parameter	Symbol	Min	Max	Unit
Laser Reverse Voltage	VRLMAX	—	2	V
dc Forward Current	IFLMAX	—	150	mA
Operating Case Temperature Range	TC	–40	70	°C
Storage Case Temperature Range*	Tstg	–40	85	°C
Photodiode Reverse Voltage	VRPDMAX	—	10	V
Photodiode Forward Current	IFPDMAX	—	2	mA

* Does not apply to shipping container.

Handling Precautions

Power Sequencing

To avoid the possibility of damage to the laser module from power supply switching transients, follow this turnon sequence:

1.All ground connections

2.Most negative supply

3.Most positive supply

4.All remaining connections

Reverse the order for the proper turn-off sequence.

Electrostatic Discharge

CAUTION: This device is susceptible to damage as a result of electrostatic discharge. Take proper precautions during both handling and testing. Follow guidelines such as JEDEC Publication No. 108-A (Dec. 1988).

Agere Systems employs a human-body model (HBM) for ESD-susceptibility testing and protection-design evaluation. ESD voltage thresholds are dependent on the critical parameters used to define the model. A standard HBM (resistance = 1.5 k¾, capacitance = 100 pF) is widely used and, therefore, can be used for comparison purposes. The HBM ESD threshold presented here was obtained using these circuit parameters:

Parameter	Value	Unit
Human-body Model	>400	V

Mounting Instructions

The minimum fiber bend radius is 1.23 in (31.25 mm).

To avoid degradation in performance, mount the module on the board as follows:

1.Place the bottom flange of the module on a flat heat sink at least 0.5 in. x 1.180 in. (12.7 mm x 30 mm) in size. The surface finish of the heat sink should be better than 32 µin. (0.8 µm), and the surface flatness must be better than 0.001 in. (25.4 µm). Using thermal conductive grease is optional; however, thermal performance can be improved by up to 5% if conductive grease is applied between the bottom flange and the heat sink.

2.Mount four #2-56 screws with Fillister heads (M2-3 mm) at the four screw hole locations (see Outline Diagram). The Fillister head diameter must

not exceed 0.140 in. (3.55 mm). Do not apply more than 1 in./lb. of torque to the screws.

0.062 (1.58)

0.118

(3.00)

0.031 (0.79)					0.086
						(2.18)

0.140

(3.56)

0.129 (3.28) R

0.041 (1.04)

1-532

Note: Dimensions are in inches and (millimeters).

Figure 2. Fillister Head Screw

Agere Systems Inc.

3

D2570, D2526G, D2555 Wavelength-Selected	Data Sheet, Rev. 3
Direct Modulated Isolated DFB Laser Module	July 2001

D2526 Characteristics

Minimum and maximum values are testing requirements. Typical values are characteristics of the device and are the result of engineering evaluations. Typical values are for information purposes only and are not part of the testing requirements.

Table 1. Electrical Characteristics (at 25 °C laser temperature)

Parameter	Symbol	Test Conditions	Min	Typ	Max	Unit
Slope Efficiency	η	LF = 2 mW (CW)	0.06	0.09	0.13	mW/mA
Threshold Current	ITH	—	—	14	30	mA
Laser Forward Voltage	VLF	LF = 2 mW (CW)	—	1.3	1.8	V
Laser Submount Temperature	TLASER	—	20	—	30	°C
Monitor Reverse-bias Voltage*	VRMON	—	3	5	10	V
Monitor Current	IRMON	POL = 1 mW (CW)	0.1	0.3	1.5	mA
Monitor Dark Current	ID	IF = 0, VRMON = 5 V	—	0.01	0.1	μA
Input Impedance	ZIN	—	—	25	—	Ω
Thermistor Current	ITC	—	10	—	100	μA
Resistance Ratio†	—	—	9.1	—	9.6	—
Thermistor Resistance	RTH	TL = 25 °C	9.5	—	10.5	k Ω
TEC Current	ITEC	TL = 25 °C, T C = 70 °C	—	0.6	1.0	A
TEC Voltage	VTEC	TL = 25 °C, T C = 70°C	—	1.3	2.0	V
TEC Capacity	T	TC = 70 °C	—	—	50	°C

* Standard operating condition is 5.0 V reverse bias.

† Ratio of thermistor resistance at 0 °C to thermistor resistance at 50 °C.

Table 2. Optical Characteristics (at 25 °C laser temperature)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Peak Optical Output Power

PPEAK

—

2.0

—

—

mW

Center Wavelength

λc

TL = 25 °C

1528.77

—

1610.06

nm

(See Table 10.)

CW wavelength

Line Width (3 dB full width)

Δλ

Modulated at 2.5 Gbits/s

—

2

10

MHz

at rated power

Side-mode Suppression Ratio

SMSR

CW

30

—

—

dB

Optical Isolation

—

T C = 0 °C to 70 °C

30

—

—

dB

Wavelength Drift (EOL)

Δλ

Tested over

—

—

±0.1

nm

25-year lifetime

Center Wavelength Drift with

ΔλC/ TC

0 °C ≤ TC ≤ 70 °C

—

—

1

pm/°C

Case Temperature

Wavelength Temperature Tuning

—

—

—

0.095

—

nm/°C

Coefficient

Tracking Error

—

T C = –20 °C/25 °C/70 °C

—

—

1

dB

Table 3. Dispersion Performance

Parameter

Symbol

Test

Min

Typ

Max

Unit

Conditions

Dispersion Penalty for Extended Reach

DP

1800 ps/nm

—

—

2.0

dB

4	Agere Systems Inc.