1550nm Semiconductor Optical Amplifier ASOA1550N15D25GBT for Optical Communication, Fiber Sensing, LiDAR, and Test Systems

1550 nm Semiconductor Optical Amplifier for Optical Communication, Fiber Sensing, LiDAR, and Test Systems

Part Number: ASOA1550N15D25GBT | March 2026

1. Introduction

Semiconductor optical amplifiers (SOAs) are becoming an increasingly important building block in modern photonic systems. As optical designs push for higher performance, tighter integration, and smaller footprints, the SOA's combination of compact packaging, broad gain bandwidth, and direct electrical controllability positions it as a practical and versatile amplification solution.

The ASOA1550N15D25GBT from Analog Technologies, Inc. is a 1550 nm SOA designed for demanding applications in fiber optic communication, distributed sensing, LiDAR, free-space optical links, and optical test and measurement systems. It delivers 25 dB of typical small-signal gain, up to 15 dBm output power, and a 100 nm gain bandwidth (−3 dB), all within a compact butterfly package that integrates a built-in TEC and thermistor for stable thermal management.

2. Key Specifications

3. Optical Gain and Output Power

The ASOA1550N15D25GBT provides 25 dB of typical small-signal gain at 1550 nm, measured at an operating current of 250 mA with an input signal of −5 dBm. This gain level is well suited to amplification tasks ranging from boosting weak sensor return signals to compensating for insertion loss in complex optical assemblies.

Maximum output power is 13 dBm typical and up to 15 dBm, measured at an input level of +5 dBm. These two figures are measured under different conditions: the 25 dB gain applies in the small-signal (unsaturated) regime, while the 13 dBm / 15 dBm output corresponds to saturated operation. Designers should account for this distinction in link budget calculations.

The 100 nm gain bandwidth (−3 dB) centered near 1550 nm provides flexibility in wavelength allocation and accommodates channel drift, coarse WDM spacing, or broadband ASE-seeded configurations.

4. Noise Figure and Polarization Performance

The noise figure of 7 to 9 dB at 1550 nm is consistent with typical SOA performance at this wavelength. While higher than the 4-5 dB of gain-clamped EDFAs, it is fully acceptable in booster and inline amplification stages and in most sensing and instrumentation applications. For pre-amplification of very weak signals, this noise figure should be included in sensitivity and link budget analysis.

Polarization dependent gain (PDG) is ≤2.0 dB with a typical value of 1.0 dB, making the device suitable for standard single-mode fiber systems. For applications requiring strict polarization insensitivity, polarization-maintaining fiber coupling or a polarization scrambler should be considered.

5. Extinction Ratio and Optical Gating

The ASOA1550N15D25GBT achieves an extinction ratio of ≥50 dB by switching the drive current on and off, and ≥70 dB with a negative bias applied. These values confirm that the SOA can simultaneously act as a high-speed optical gate or shutter in addition to providing optical gain.

In fiber sensing applications, the SOA can replace an acousto-optic modulator (AOM) for signal chopping or pulse gating, eliminating a separate and costly modulation component. This dual function - amplification plus gating in a single device - simplifies system architecture, reduces component count, and lowers total system cost in sensing and time-domain measurement applications.

6. Thermal Management

The ASOA1550N15D25GBT integrates a built-in TEC (thermoelectric cooler) rated at up to 3.4 V and 1.8 A, together with a 10 kΩ (typ) NTC thermistor for closed-loop temperature feedback. The TEC maintains the SOA chip at a stable operating point, which is essential for reproducible gain, stable output wavelength, and long device lifetime. The thermistor output is compatible with standard ATI TEC controllers and other PID-based temperature control circuits.

The device is rated for operation from −10°C to +70°C ambient with approximately 4 W total power consumption including TEC overhead. For outdoor or wide-temperature deployments, supplemental cooling or an insulated enclosure should be evaluated alongside the on-board TEC.

7. Applications

7.1 Fiber Optic Sensing Systems

The high extinction ratio (≥50 dB on/off, ≥70 dB with negative bias) allows this SOA to perform optical amplification and pulse gating in a single component, replacing the AOM used for modulation or chopping in distributed temperature sensing (DTS), distributed acoustic sensing (DAS), and OTDR systems.

7.2 LiDAR and Wind Measurement Radar

In coherent LiDAR and Doppler wind-sensing systems, the ASOA1550N15D25GBT can serve as a booster amplifier for the transmitted optical pulse or as a pre-amplifier for the received return signal. Direct electrical control of gain and gating simplifies integration into pulsed LiDAR transmitters and reduces active component count.

7.3 Optical Communication - Pre-Amplification and Booster Amplification

The device is suited for booster and inline amplification in short- to medium-reach fiber links where an EDFA would be oversized or too costly. It can partially substitute for EDFA in cost-sensitive or space-constrained deployments, trading a somewhat higher noise figure for significantly smaller size, simpler drive electronics, and lower system cost.

7.4 Free-Space Optical (FSO) Links

The compact butterfly package and moderate power consumption are attractive for FSO terminal designs where SWaP constraints are common. Built-in TEC support enables stable operation across the temperature ranges typically encountered in outdoor FSO installations.

7.5 Optical Test and Measurement

As a wideband, gain-adjustable 1550 nm amplifier, this SOA is useful as a signal booster in optical network analyzers, component test benches, and coherent receiver evaluation platforms. Its 100 nm gain bandwidth supports multi-channel or swept-wavelength testing across a wide portion of the C and L bands.

8. SOA vs. EDFA: Practical Considerations

The table below summarizes the key differences between semiconductor optical amplifiers and erbium-doped fiber amplifiers to help designers select the right technology for their application.

For system designers, the choice between SOA and EDFA depends primarily on the noise budget, physical size constraints, and whether optical gating functionality is required. The ASOA1550N15D25GBT is the stronger choice wherever compactness, switching speed, or cost efficiency is the priority.

9. Technical Notes

• Small-signal gain (25 dB) and maximum output power (13 dBm typ / 15 dBm max) are measured under different input conditions and should not be combined in a single link budget without accounting for gain compression.
• The ASE spectral center is at 1515 nm, while the device is optimized for signal amplification at 1550 nm. In ASE-seeded or broadband applications, the ASE spectral shape should be considered separately.
• Extinction ratio ≥70 dB (negative bias): applying a small reverse voltage to the SOA contact further suppresses residual output, making the device usable as a high-isolation optical switch.
• Total power consumption ~4 W includes both the SOA drive current (250-400 mA at 1.3-1.5 V, equating to ~0.3-0.6 W for the active region) and the TEC power (up to 3.4 V × 1.8 A = 6.1 W max capacity), with the TEC overhead constituting the majority of the 4 W typical total.
• The 10 kΩ thermistor is an NTC type. Its resistance decreases with rising temperature and serves as the feedback element for closed-loop TEC control.

10. Ordering Information

11. Recommended Laser Drivers: ATLS500MA104 and ATLS500MA103

For driving a seed laser diode or any diode laser at up to 500 mA in a photonic system built around the ASOA1550N15D25GBT, ATI offers two proven 500 mA constant-current laser drivers: the ATLS500MA104 and the ATLS500MA103. Both are housed in the same compact 6-sided metal DIP package with identical footprint and pin-out, and both deliver the low-noise, stable current that diode lasers and SOA-seeding applications require. The primary difference between them is noise performance: the ATLS500MA104 achieves lower output noise of less than 0.6 μA_RRMS at 0.1 Hz to 10 Hz, while the ATLS500MA103 is specified at ≤5 μA_P-P over the same bandwidth. Both are well suited to DPSSL, EDFA, SOA, fiber laser, and sensing applications.

Key features shared by both models:

• 6-sided metal enclosure: complete EMI shielding in both directions, protecting the SOA and surrounding photonics electronics from interference.
• Independently programmable output current and current limit via 0-2.5 V analog input - fully compatible with DAC-based digital control.
• Laser current output indication (LIO pin): real-time 0-2.5 V analog output proportional to actual output current for continuous monitoring.
• Loop good indicator (LPGD pin): digital output confirms the control loop is operating correctly.
• Internal temperature monitoring (TMPO pin): analog output for host-system thermal management.
• Automatic over-temperature shutdown at 120°C: protects both the laser diode and the driver.
• 2.5 V precision internal reference for current setting and external ADC/DAC use.
• Compact DIP package: 20 × 14.5 mm, 5 mm thick. DIP and SMT packages available.
• RoHS and 100% lead-free compliant.

Choose the ATLS500MA104 when the lowest possible noise is required. Choose the ATLS500MA103 when the application is less noise-sensitive and the wider 1 MHz modulation bandwidth or single-pin shutdown control is preferred.

12. Recommended TEC Controller: TECA1-5V-3.5V-DAH

The ASOA1550N15D25GBT integrates a built-in TEC rated at up to 3.4 V and 1.8 A, paired with a 10 kΩ NTC thermistor. To drive this TEC for closed-loop temperature stabilization - or to regulate any TEC in the broader photonic system - the TECA1-5V-3.5V-DAH is the recommended ATI TEC controller. Powered from a standard 5 V supply, it provides up to 3.5 V across the TEC (covering the SOA's 3.4 V maximum) and up to 2.5 A output current, with a temperature stability of 0.004°C.

The TECA1LD-5V-3.5V-DAH variant (with the "LD" suffix) includes an internal compensation network pre-matched to butterfly-packaged TEC thermal loads, reducing external component count and simplifying PCB design when driving SOA-style packages.

Key features:

• High efficiency: ≥90% - H-bridge PWM architecture; no heat sink required in most designs.
• Maximum output current: 2.5 A; maximum TEC voltage: 3.5 V - fully covers the SOA built-in TEC (rated 3.4 V / 1.8 A).
• Temperature stability: 0.004°C - essential for wavelength stability and consistent SOA gain performance.
• Zero EMI: 6-sided gold-coated metal enclosure shields all PWM switching noise from surrounding laser driver and detection electronics.
• Actual object temperature monitoring (TEMP pin): real-time analog output (0 V to V_VPS) proportional to thermistor temperature; maps to 15°C-50°C by default with the internal network.
• Temperature good indicator (TEMPGD pin): digital output confirms set-point has been reached within 0.1°C - use as a system-ready interlock before enabling the SOA drive current.
• Programmable set-point (TEMPSP pin): set by potentiometer or DAC using the built-in 3.0 V precision reference.
• Shutdown control (SDNG pin): independent power-down without affecting other system rails.
• Internal compensation network option (TECA1LD variant): pre-configured for butterfly TEC packages, simplifying PCB design.
• Compact DIP package: 25.4 × 19.9 mm. RoHS and 100% lead-free compliant.

For More Information

Analog Technologies, Inc. • 1161 Ringwood Ct., #110, San Jose, CA 95131, U.S.A.
Tel: 408-748-9100 • www.analogtechnologies.com