1241 AGERE | Alldatasheet

Document overview

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Technical content

Features

I Backward compatible with 1227/1229/1238-Type Laser Transmitters I Space-saving, self-contained, 20-pin DIP I Uses field-proven, reliable InGaAsP MQW laser I Requires single 5 V power supply I SONET/SDH compatible I Uncooled laser with automatic optical power con- trol for constant output power over case tempera- ture range I No thermoelectric cooler required; reduces size and power consumption I Uses low-power dissipation CMOS technology I Qualified to meet the intent of Bellcore reliability practices I Operates over data rates to 1062.5 Mbits/s (NRZ) I Operation at 1.3 µm or 1.55 µm wavelength I T ypical average output power options of –11 dBm, –8 dBm, –5 dBm, –2 dBm, and 0 dBm I ECL compatible, differential inputs I Operating temperature range of –40 °C to +85 °C I T ransmitter-disable option

Applications

— Inter- and intraoffice SONET/ITU-T SDH — Subscriber loop — Metropolitan area networks I High-speed data communications — Fibre channel (FC-0)

2 Agere Systems Inc. Data Sheet 1241/1243/1245-Type Uncooled Laser Transmitter September 1999

Description

The 1241/1243/1245-type Laser Transmitters are designed for use in transmission systems and high- speed data communication applications. Used in intraoffice and intermediate-reach applications, the transmitters are configured to operate at SONET rates up to OC-12, as well as at ITU-T synchronous digital hierarchy (SDH) rates up to STM-4. Specific versions are also capable of operating up to 1062.5 Mbits/s. The transmitter meets all present Bellcore GR-253- CORE requirements, ANSI T1.117-1991 SONET sin- gle-mode, and the ITU-T G.957 and G.958 recommen- dations. (See Table 5 to select transmitters for the various SONET/SDH segments.) The transmitter requires a single power supply (+5 V or –5 V) and operates over data rates of 1 Mbits/s to 622 Mbits/s (NRZ). Automatic power control circuitry provides constant optical output power over the operat- ing case temperature range. The automatic power con- trol circuitry also compensates for laser aging. The optical wavelength tolerance at 25 °C is 1310 nm. The temperature coefficient of wavelength for 1.3 µm Fabry- Perot transmitters (1241- Type) is approximately 0.4 nm/°C. The temperature coefficient of wavelength for 1.3 µm and 1.55 µm distributed-feedback (DFB) transmitters (1243/1245-Type) is approximately 0.1 nm/°C. T ransmitters are available for operation over several dif- ferent temperature ranges from –40 °C to +85 °C. Man- ufactured in a 20-pin DIP , the transmitter consists of a hermetic, InGaAs laser and a single CMOS driver IC. The low-power consumption circuit provides modula- tion, automatic optical output power control, and data reference. The module can be driven by either ac- or dc-coupled data in single-ended or differential configu- ration. (See Recommended User Interfaces section for typical connection schemes.) The laser bias and back- facet monitor currents are electrically accessible for transmitter performance monitoring. The transmitter optical output may be disabled by a logic-level input. Functional Overview Transmitter Circuit Description and Operation Figure 1 shows a simplified schematic of the transmit- ter; pin information is listed in T able 1. The laser within the transmitter is driven by a single CMOS integrated circuit, which provides the input data signal reference level with automatic, temperature-compensated laser bias, and modulation-current control. A back-facet pho- todetector diode within the laser module provides an indication of the laser's average optical output power. The back-facet diode current is accessible as a voltage proportional to photocurrent through pins 17 and 19 on the transmitter. The back-facet diode also forms part of the feedback control circuit, which helps maintain con- stant output power. The laser bias current is accessible as a dc-voltage by measuring the voltage developed across pins 2 and 4 of the transmitter. Dividing this voltage by 10 Ω will yield the value of the laser bias current. This value will change up or down in response to operating tempera- ture, power supply voltage, data pattern, and laser aging characteristics. Table 1. Pin Descriptions ground or any other circuit potential.

1 No user connection *

2 Laser bias monitor (+) †

3 No user connection *

4 Laser bias monitor (–) †

7 T ransmitter disable

10 No user connection †

11 Case ground (RF ground)

12 V CC

13 Case ground (RF ground)

15 DA TA

16 DA TA

17 Laser back-facet monitor (–)

18 V CC

19 Laser back-facet monitor (+) *

20 No user connection †

Figure 1. Simplified Transmitter Schematic Input Data Data enters the transmitter through a comparator. CC – 1.3 V to eliminate pulse-width distortion.

4 Agere Systems Inc. Data Sheet 1241/1243/1245-Type Uncooled Laser Transmitter September 1999 Functional Overview (continued) Since most applications operate at very high data rates, high-frequency design techniques need to be used to ensure optimum performance from the trans- mitter and interfacing circuitry. Input signal paths should be kept as short and as straight as possible; dif- ferential signal lines should be equal in length, and controlled-impedance stripline or microstrip construc- tion should always be used when laying out the printed- wiring board traces for the data lines. The Recom- mended User Interfaces section of this data sheet shows several methods of interfacing to the transmitter. Power Supplies The transmitter is configured for operation from either a single +5 V power supply or a single –5 V power sup- ply. For positive power supply operation, connect Vcc to the +5 V power supply and connect V EE to ground or circuit common. For operation from a –5 V power sup- ply, connect V CC to ground and connect VEE to the –5 V power supply . Whichever option is chosen, the VCC or VEE connection to the transmitter should be well filtered to prevent power supply noise from interfering with transmitter operation. Transmitter Specifications Optical Output Power During manufacture, the optical output power of every transmitter is tuned to the typical value specified in the data sheet for that particular transmitter code. The tun- ing is performed at room ambient and a power supply voltage of 5 V . The minimum and maximum values listed in the data sheet for each code group reflect the worst-case limits that the transmitter is expected to operate within over its lifetime and over the allowed power supply and the operating temperature range. Every transmitter shipped receives a final test, which includes a SONET eye-mask test at either the OC-3 (STM-1) data rate of 155.52 Mbits/s, the OC-12 (STM4) data rate of 622.08 Mbits/s, or the fibre channel FC-0 data rate of 1062.5 Mbits/s. The eye-mask test is meant to examine the performance of the transmitter's output optical waveform relative to a minimum data pat- tern eye opening. Connector Options The standard optical fiber pigtail is 8 µm core single- mode fiber having a 0.036 in. (914 µm) diameter tight- buffered outer-jacket. The standard length is 39 in. ± 4 in. (1 m ± 10 cm) and can be terminated with either an SC or FC-PC optical connector. Other connector options may be available on special order. Contact your Agere Account Manager for ordering information. Handling Precautions CAUTION: This device is susceptible to damage as a result of electrostatic discharge (ESD). Take proper precautions during both handling and testing. Follow guidelines such as JEDEC Publication No. 108-A (Dec. 1988). Although protection circuitry is designed into the device, take proper precautions to avoid exposure to ESD. Agere employs a human-body model (HBM) for ESD-susceptibility testing and protection-design evalu- ation. ESD voltage thresholds are dependent on the critical parameters used to define the model. A stan- dard HBM (resistance = 1.5 kΩ , capacitance = 100 pF) is widely used and, therefore, can be used for compari- son purposes. The HBM ESD withstand voltage estab- lished for the 1241-/1243- Typ e Transmitter is ±1000 V. Transmitter Processing The transmitter can withstand normal wave-soldering processes. The complete transmitter module is not her- metically sealed; therefore, it should not be immersed in or sprayed with any cleaning solution or solvents. The process cap and fiber pigtail jacket deformation temperature is 85 °C. Transmitter pins can be wave- soldered at maximum temperature of 250 °C for 10 seconds. Installation Considerations Although the transmitter features a robust design, care should be used during handling. The optical connector should be kept free from dust, and the process cap should be kept in place as a dust cover when the device is not connected to a cable. If contamination is present on the optical connector, canned air with an extension tube can be used to remove any debris. Other cleaning procedures are identified in the techni- cal note, Cleaning Fiber-Optic Assemblies (TN95- 010LWP).

periods can adversely affect device reliability. *W i t h VEE connected to –5 V , VCC must be at 0 V; with VCC connected to +5 V , VEE must be at 0 V. after a warm-up time determined by the system thermal design. end of life (EOL). Typical values are measured at beginning-of-life (BOL) room temperature unless otherwise noted. Table 2. Electrical Characteristics

  1. With VEE connected to –5 V, VCC must be at 0 V; with VCC connected to +5 V , VEE must be at 0 V .
  2. Input measured from VCC with 50 Ω load to (VCC – 2 V). 10K, 10K H, and 100K ECL compatible.
  3. Between 10% and 90% (50% duty cycle) where t is the bit period in ns.
  4. The transmitter is normally enabled and only requires an external voltage to disable.
  5. Time measured from rising edge of disable signal until optical output (laser diode) has turned off.
  6. Time measured from falling edge of enable signal until optical output has stabilized at nominal output power level.
  7. The laser bias current is obtained by dividing the bias voltage by the 10 Ω current-sensing resistors. (See Figure 1.) When measuring these

voltages or using them in conjunction with alarm circuits, use a high-input impedance device.

  1. The laser back-facet monitor voltage is a scaled output that tracks the transmitter optical output power.

Table 3. Optical Characteristics

  1. Output power definitions and measurement per ITU-T Recommendation G.957 and G.958.
  2. Ratio of logic 1 to logic 0 power levels.
  3. Between 10% and 90% (50% duty cycle).
  4. Root-mean-square spectral width accounts for modes up to and including those 20 dB down from the central mode.
  5. Applies to 1243/1245-Type only.
  • Locate these components as close to DATA/DA TA inputs as possible.

Note: The 1241 gigabit version does not require the external 50 Ω terminations since this termination is included inside the module. Figure 2. dc-Coupled, Differential Input

1062.5 Mbits/s

88 Agere Systems Inc. Data Sheet September 19991241/1243/1245-Type Uncooled Laser Transmitter Outline Diagram Dimensions are in inches and (millimeters). Unless otherwise noted, tolerances are ±0.005 in (±0.127 mm). 1-987C).a 1.339 (34.01) 0.950 (24.13) 0.635 (16.14) 0.144 (3.66) TOP VIEW PIN 1 INDICATOR 0.125 (3.18) 0.110 (2.80) 0.100 (2.54) 0.900 (22.86) 0.350 (8.89) 0.400 (10.16) PIN 20PIN 11 PIN 1PIN 10 BOTTOM VIEW 0.018 (0.46)

number 8720009. All versions are Class I laser products per IEC 825-1:1993. hazardous laser radiation exposure. This product complies with 21 CFR 1040.10 and 1040.11. Unterminated optical connectors may emit laser radiation. Do not view with optical instruments. Table 4. Agere Transmitters for SONET/SDH Applications

  • Full SONET/SDH compliance, –40 °C to +85 °C.

† Full SONET/SDH compliance, –20 °C to +70 °C.

1010 Agere Systems Inc. Data Sheet September 19991241/1243/1245-Type Uncooled Laser Transmitter

Ordering Information

Table 5. 1241/1243/1245-Type Transmitter Ordering Information

  • ∆λ for these codes is 2.5 nm maximum. All other 1241-type codes are 4 nm maximum.

Table 6. Related Products

155 Mbits/s and 622 Mbits/s for SONET/

155 Mbits/s and 622 Mbits/s Receivers

Agere Systems Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liabi lity is assumed as a result of their use or application. Copyright © 2001 Agere Systems Inc. All Rights Reserved September 1999 DS99-228LWP (Replaces DS99-073LWP) For additional information, contact your Agere Systems Account Manager or the following: INTERNET: http://www.agere.com E-MAIL: docmaster@agere.com N. AMERICA: Agere Systems Inc., 555 Union Boulevard, Room 30L-15P-BA, Allentown, P A 18109-3286 1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106) ASIA: Agere Systems Hong Kong Ltd., Suites 3201 & 3210-12, 32/F , T ower 2, The Gateway, Harbour City, Kowloon Tel. (852) 3129-2000, FAX (852) 3129-2020 CHINA: (86) 21-5047-1212 (Shanghai), (86) 10-6522-5566 (Beijing), (86) 755-695-7224 (Shenzhen) JAPAN: (81) 3-5421-1600 (T okyo), KOREA: (82) 2-767-1850 (Seoul), SINGAPORE: (65) 778-8833, T AIWAN: (886) 2-2725-5858 (T aipei) EUROPE: Tel. (44) 7000 624624, FAX (44) 1344 488 045