Wavelength-Selected High-Power D2587P-Type (with Wavelength Locker)/D2547P-Type Isolated DFB Laser Modules

Telecommunications: Dense WDM SONET/SDH OC-192/STM-64 Extended and ultralong reach Undersea systems Digital video

The D2587P-Type DFB laser module is designed for use with an external lithium niobate modulator and also in applications where high power (20 mW) is required. The use of an internal wavelength locker greatly enhances long-term reliability and reduces chirp and mode dispersion when used in conjunction with LN modulators at OC-192 data rates. A companion device, the D2547P high-power DFB laser module, is also designed for use with a lithium niobate external modulator, but without the use of an internal wavelength locker.

Featuring wavelength selection and locking capabilities, the D2587P Laser Module is ideally suited for use with external lithium niobate modulators, and in high-power (20 mW) applications.

High-performance, multiquantum-well (MQW), distributed-feedback (DFB) laser D2587P-Type is offered on 50 GHz ITU grid wavelengths ranging from 1528.77 nm-- D2547P-Type is offered on 100 GHz ITU grid wavelengths ranging from 1528.77 nm-- 1610.06 nm Polarization-maintaining fiber pigtail For use with lithium niobate modulators High optical power (20 mW, CW) Hermetic, 14-pin package

Wavelength-Selected, High-Power D2587P-Type (with Wavelength Locker)/D2547P-Type Isolated DFB Laser Modules

The single-channel, wavelength-selected DFB (ILM) package contains internal wavelength-discriminating optics, i.e., two etalons and associated photodiodes. The output consists of analog signals suitable for controlling the electrical current of the thermoelectric cooler (TEC) and the DFB laser.

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.

* Fujikura is a registered trademark of Fujikura Ltd. Telcordia Technologies is a trademark of Telcordia Technologies Inc. � ISO is a registered trademark of The International Organization for Standardization.

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.

CORE STRESS ROD PRINCIPLE POLARIZATION AXIS CLADDING INNER COATING (SILICON & ACRYLATE) OUTER COATING

An integral TEC provides stable thermal characteristics. The TEC allows for heating and cooling of the laser chip to maintain a temperature 25 �C for case temperatures from 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.

Pin D2587P-Type Thermistor Laser dc Bias (Cathode) Back-facet Monitor Anode Back-facet Monitor Cathode TEC (+)1 TEC (�)1 Case Ground Photodiode 2 Anode Photodiode 1 Anode Laser Anode 2 RF Laser Input Cathode Laser Anode NC D2547P-Type Thermistor Laser dc Bias (Cathode) Back-facet Monitor Anode Back-facet Monitor Cathode TEC (+)1 TEC (�)1 Case Ground

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.

The laser module is fabricated 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 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 the Agere Systems Inc. lithium niobate modulators. It has a mode field diameter of 10.5 �m, a cladding diameter �m �3 �m, and a loose tube jacketed fiber �m in diameter. Figure 1 shows the orientation of polarization in the fiber.

1. A positive current through the thermoelectric heat pump cools the laser. 2. Both leads should be grounded for optimum performance.

VOLTAGE PROPORTIONAL TO WAVELENGTH VOLTAGE PROPORTIONAL TO OPTICAL POWER VOLTAGE PROPORTIONAL TO TEMPERATURE