AGERE D2525P884, D2525P883, D2525P882, D2525P881, D2525P880 Datasheet

Data Sheet

March 2000

Wavelength-Selected D2525P

Isolated DFB Laser Module with PMF

The 1.5 m D2525P Laser Module is available in a 14-pin, hermetic, butterfly package.

Features

■ITU wavelengths available from 1529.55 nm —1610.06 nm

■Integrated optical isolator

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

■Industry-standard, 14-pin butterfly package

■Hermetic package

■InGaAs, PIN photodetector back-facet monitor

■Polarization-maintaining fiber pigtail

■For use with lithium niobate modulators

■High reliability

■Narrow linewidth

■High optical power available

Applications

■Telecommunications

—SONET/SDH OC-48/STM-16, OC-192/STM-64

—Extended and ultralong reach

—Undersea systems

—Dense WDM systems

■Digital video

Description

The D2525P family of DFB laser modules is designed to be used with a lithium niobate external modulator (see Table 4). The laser module features a polarization-maintaining fiber (PMF) pigtail, enabling it to be directly connected to a modulator without the need of a polarization controller. The PMF maintains the polarization of the output light to a consistent orientation. This allows the D2525P to be used as a CW light source for systems requiring extremely low chirp such as undersea or 10 Gbits/s systems. The module contains a multiquantum-well (MQW), distributedfeedback (DFB) laser. This device nominally has an output power of 10 mW. The wavelength of the laser can be temperature-tuned for more precise wavelength selection by adjusting the temperature of the internal thermoelectric cooler.

Wavelength-Selected D2525P	Data Sheet
Isolated DFB Laser Module with PMF	March 2000

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 backfacet 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 that separates the dc-bias path from the RF input. The RF input has a nominal 25 Ω impedance.

The laser module is equipped with Fujikura* polarizationmaintaining fiber (PMF). The fiber is PANDA type and is the same fiber that is used on Lucent Technologies Microelectronics Group’s lithium niobate modulators. It has a mode field diameter of 10.5 µm, a cladding diameter of 123 µm— 128 µm, and a loose tube jacketed fiber 900 µm in diameter. The pigtail is terminated with an ST ® ferrule†. Figure 1 shows the orientation of polarization in the fiber.

Lucent’s 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.

* Fujikura is a registered trademark of Fujikura Ltd.

†The ST ferrule key is not aligned to slow axis of fiber. Connector is intended for testing purposes only.

‡Telcordia Technologies is a trademark of Bell Communications Research, Inc.

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

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CORE

STRESS ROD

PRINCIPAL POLARIZATION

AXIS

CLADDING

INNER COATING (SILICON & ACRYLATE)

OUTER COATING (ACRYLATE OR NYLON)

1-771(C).a

Figure 1. Polarization-Maintaining Fiber

Pin Information

Table 1. Pin Descriptions

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

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

2.Both leads should be grounded for optimum performance.

7	6	5	4	3	2	1
–	+	+	–	–
			L1		TH
			160 nH
	TEC				10 kΩ
				R1	ISOLATOR
					Ω
	PACKAGE			20
	GROUNDS
			+	–	+
8	9	10	11	12	13	14	1-567

Top view.

Figure 2. Circuit Schematic

Lucent Technologies Inc.

Data Sheet	Wavelength-Selected D2525P
March 2000	Isolated DFB Laser Module with PMF

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 operations sections 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	—	225	mA
Operating Case Temperature Range	TC	–40	70	°C
Storage Case Temperature Range*	Tstg	–40	70	°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 turn-on 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).

Lucent employs a human-body model (HBM) for ESDsusceptibility 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 kΩ, 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
Lucent Technologies Inc.

Mounting Instructions

The minimum fiber bend radius is 1.50 in.

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(C)

Note: Dimensions are in inches and (millimeters).

Figure 3. Fillister Head Screw

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