Document
Data Sheet March 2000
Wavelength-Selected D2525P Isolated DFB Laser Module with PMF
Applications
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Telecommunications — SONET/SDH OC-48/STM-16, OC-192/STM-64 — Extended and ultralong reach — Undersea systems — Dense WDM systems Digital video
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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.
The 1.5 µm D2525P Laser Module is available in a 14-pin, hermetic, butterfly package.
Features
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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
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Wavelength-Selected D2525P Isolated DFB Laser Module with PMF
Data Sheet 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.
CORE STRESS ROD
PRINCIPAL POLARIZATION AXIS CLADDING INNER COATING (SILICON & ACRYLATE) OUTER COATING (ACRYLATE OR NYLON)
1-771(C).a
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.
Figure 1. Polarization-Maintaining Fiber
Pin Information
Table 1. Pin Descriptions
Pin Name Thermistor Thermistor Laser dc Bias (Cathode) (–) Back-facet Monitor Anode (–) Back-facet Monitor Cathode (+) Thermoelectric Cooler (+)1 Thermoelectric Cooler (–)1 Case Ground Case Ground Case Ground Laser Anode (+) 2 RF Laser Input Cathode (–) Laser Anode (+) 2 Case Ground
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 circuitr.