Polarization Maintaining Erbium Doped Fiber Amplifier (EDFA)

How an erbium-doped fibre amplifier works

An EDFA amplifies light directly in the optical domain. A length of fibre doped with erbium ions is pumped by a laser diode, typically at 980 nm or 1480 nm. The pump excites the erbium ions, and incoming C-band signal photons stimulate them to release their energy as identical photons, amplifying the signal without converting it to electronics. EDFAs are the workhorse amplifiers of fibre communications because they offer high gain, low noise and wide bandwidth around 1550 nm.

Why polarisation maintaining matters

In ordinary single-mode fibre, the polarisation state wanders with temperature, bending and vibration. A standard EDFA built from such fibre outputs light with unpredictable, drifting polarisation. That is acceptable for traditional telecom links, but not for:

• Mach-Zehnder and IQ modulators, which only modulate one polarisation correctly.
• Coherent receivers and local oscillators, where LO polarisation must match the hybrid.
• Interferometric sensors and fibre gyroscopes, whose fringes depend on polarisation.
• Coherent beam combining and free-space terminals, which need a stable, known polarisation.

A PM EDFA uses PM fibre and PM components throughout, so linearly polarised input light stays linearly polarised at the output.

Single-channel or DWDM gain-flattened

The single-channel version is optimised for amplifying one laser line, for example a tunable laser feeding a modulator, a local oscillator or a free-space transmitter. The multi-channel version is gain-flattened across the C-band so that many DWDM channels, for example a CoBrite MX comb combined in a PMUX, are amplified uniformly without one channel dominating.

Choosing the output power

Output power options run from +13 dBm (20 mW) to +30 dBm (1 W). Lower-power units suit driving a modulator or compensating insertion losses on a test bench. Higher-power units are used for loading many DWDM channels, splitting light to many devices, free-space transmission and nonlinear optics.

Order Code Options

Polarisation extinction ratio, gain and exact wavelength range depend on configuration. Contact United Spectrum Instruments for the datasheet of your selected model.

All-PM Optical Path

Every fibre and component in the signal path is polarisation maintaining, so linearly polarised input light leaves the amplifier linearly polarised with a high extinction ratio, ready for modulators, coherent receivers and interferometers.

Six Output Power Options up to +30 dBm

Choose +13, +18, +20, +23, +27 or +30 dBm saturated output to match your application, from boosting a single laser to driving a modulator, to loading many DWDM channels or feeding a free-space terminal.

Single-Channel or DWDM Gain-Flattened

The single-channel version amplifies one laser line; the multi-channel version is gain-flattened so a full DWDM comb is amplified evenly. Both preserve polarisation.

Low Noise Figure

A noise figure below 5.5 dB keeps added amplified spontaneous emission low, preserving OSNR for coherent and multi-level signals.

Current or Power Control

Automatic current control (ACC) gives a stable pump setting, while the automatic power control (APC) option holds output power constant as input power varies.

Benchtop or 1 HE Rack Housing

The turn-key benchtop unit suits lab benches; the 1 HE 19″ rack version integrates with CoBrite MX mainframes, PMUX multiplexers and other rack equipment.

Easy Local and Remote Operation

A front panel with LCD display, key switch and power-adjust knob allows hands-on control. RS232 remote control with LabVIEW software is included, and Ethernet is available as an option.

Connector Choice

FC/APC, FC/PC, SC/APC or SC/UPC connectors are available to match your existing patch cords and instruments.

Amplifying DWDM Channel Combs

After a PMUX combines many CoBrite MX lasers, the gain-flattened multi-channel PM EDFA restores the power lost in multiplexing and modulation while keeping every channel aligned, so the comb can drive downstream modulators and line systems.

Transmitter Power Enhancement

Coherent and IQ modulators introduce significant insertion loss. A PM EDFA before or after the modulator, for example with an OMFT transmitter, raises signal power for transmission experiments without disturbing polarisation.

Local Oscillator Boosting

When one tunable laser must feed several coherent receivers as a shared local oscillator, a single-channel PM EDFA provides the extra power while keeping the LO polarisation aligned to each optical hybrid.

Free-Space and Satellite Optical Communication

Free-space optical terminals for satellite and space communication need high, linearly polarised transmit power. Output options up to +30 dBm support laboratory and field link testing.

Defence and Secure Communication

For defence and secure communication programmes, the PM EDFA supports coherent link testing, free-space terminals and polarisation-sensitive photonic systems.

Coherent LiDAR and Fibre Sensing

For coherent LiDAR, interferometric sensing and fibre-optic gyroscope development, the PM EDFA amplifies the transmit beam while preserving the polarisation that interference depends on.

Coherent Beam Combining and Nonlinear Optics

Coherent beam combining, frequency conversion and quantum photonics pump stages all require amplified light with a fixed polarisation, which the all-PM design delivers.

Official Authorised Distributor in India

United Spectrum Instruments is the authorised Indian distributor for ID Photonics, so you receive a genuine PM EDFA backed by the manufacturer.

Help Choosing Power, Type and Housing

We review your input power, number of channels, required output and setup, and recommend the right output option, single-channel or DWDM version, control mode and housing.

Experience with Indian Research and Industry

We work with IITs, CSIR laboratories, defence establishments, telecom companies and photonics start-ups across India and understand their procurement and documentation requirements.

Delivery and Local Technical Support

We deliver anywhere in India and provide after-sales support for installation, remote control setup and troubleshooting.

A Complete PM Signal Chain

Alongside the PM EDFA, we supply CoBrite tunable lasers, PMUX multiplexers, OMFT transmitters, CORX receivers and optical spectrum analysers, so your full polarisation-maintaining setup can come from one partner.

Contact Us

Phone: +91 93631 83748 / +91 97899 04948
Email: sales@unitedspectrum.in