ThorLabs MX40B-1310 40 Gb/s Max Digital Reference Transmitter, 1310 nm Laser, Limiting Amplifier

The ThorLabs MX40B-1310 is a 40 Gb/s digital reference transmitter engineered for high-speed optical communication system testing and component characterization. It features an internal 1310 nm fixed-wavelength laser paired with a limiting amplifier delivering 30 dB gain across a 20 GHz small-signal bandwidth. The instrument integrates a Mach-Zehnder intensity modulator with bias control and variable optical attenuation for precise output power management.

Its limiting amplifier provides user-adjustable RF output swing from 3 V to 7 V, supporting Return-to-Zero (RZ), Non-Return-to-Zero (NRZ), and On-Off Keying (OOK) modulation formats across the full 40 Gb/s data rate.

Technical Specifications

• Maximum bit rate: 40 Gb/s


• Internal laser wavelength: 1310 nm (fixed)


• Small-signal bandwidth: 20 GHz


• Low-frequency cutoff: 100 kHz


• Limiting amplifier gain: 30 dB


• Amplifier RF output swing: 3 V to 7 V (user-adjustable)


• Optical output power: 13.5 dBm typical (22.39 mW)


• RF optical extinction ratio: 13 dB typical maximum


• Polarization extinction ratio: 18 dB


• Lambda/2 wave voltage: 5.5 V


• Electrical return loss: -10 dB typical


• Response time: 1 s

Key Features

• Mach-Zehnder intensity modulator with integrated bias control


• Variable optical attenuator for power management


• Differential RF signal input


• Intuitive touchscreen interface with USB and RS-232 control


• External laser modulation capability (1250 nm to 1610 nm wavelength range) via loop-back configuration


• RoHS exempt


• One-year warranty; light source warranty limited to one year or specified operating hours

Typical Applications

• High-speed optical component and system characterization


• 40 Gb/s digital signal generation for test and validation


• Modulation format validation (RZ, NRZ, OOK)


• Optical communication system testing at 1310 nm

Compatibility & Integration The MX40B-1310 accepts external laser sources within the 1250 nm to 1610 nm range through external loop-back configuration, enabling customized wavelength implementations while retaining the unit's modulation and amplification capabilities.