Month: September 2017

How High Quality PM Filter WDM Helps in Better Optical Fiber Communication?

Polarization Maintaining Filter Wavelength Division Multiplexer (PM Filter WDM) is best for high speed WDM network systems. It maintains signal polarization while providing wavelength division multiplexing. It is totally dependent on environmentally stable thin films filter technology with high return loss.

What is the need for Wavelength Division Multiplexing?

PM FWDM

It can be said as the technology which is multiplexing various optical signals onto a single fiber. It is incorporated using different wavelengths of laser light enabling bi-directional communications over fiber connections. It is different from frequency division multiplexing which is applied to a radio carrier. As the name suggest, multiplexer transmit several signals together. It is popular among telecommunication industry because without laying more optical fiber companies can expand the capacity of the network.

Why to use PM Filter WDM?

  1. It can be used best to maintain polarized fiber amplifiers and is used in DWDM systems.
  2. With help of this WDM, high speed communication systems are developed.
  3. It also helps in the development of instrumental applications.

Features of PM Filter WDM

Listed below are some of the PM Filter WDM features –

  • It has high extinction ratio.
  • High return ratio.
  • Great reliability and strong environmental stability.
  • Low insertion loss.

PM Filter WDM is used for applications like EDFAs, fiber sensing system, WDI module and many more. Compliance is maintained in terms with RoHS and Telcordia GR-1221-CORE. While designing and manufacturing ITU standards should be followed. PM Filter WDM is used by companies and individuals to perform drop function or adding a single channel. It is used on sensor systems with advanced packaging technology.

Performance Specification of PM Filter WDM

Here are detailed specifications of the WDM –

Parameter Unit T1550/R980 T980/R1550
Transmission Wavelength Range nm 1520~1580 960~990
Reflect Wavelength Range nm 960~990 1520~1580
Max. Insertion Loss Transmission dB 0.8
Reflect dB 0.5
Min. Isolation Transmission dB 25
Reflect dB 12
Min. Extinction Ratio dB 20
Min. Channel Flatness dB 0.3
Min. Return Loss dB 50
Max. Power Handling(CW) W 0.3, 0.7, 1, 2, 3, 10
Max. Tensile Load(N) N ≤5
Fiber Type – PM Panda fiber
Operating Temperature ℃ -5 to +70
Storage Temperature ℃ -40 to +85
Package Dimensions mm Ø5.5 x L35

Specifications can be changed or altered as required. Also, the values specified are not subjected to any connector loss. PM fiber and the connector key are aligned to slow axis. This product can also be used to multiplex other wavelengths, including 980/1064 PM WDM nm (pulsed laser applications) and 1064/1550 nm (Erbium-Ytterbium pumping). Low power (300 mW, 500 mW) and high power (5W) handling are available.It can also be provided with a PM isolator integrated in the same package. They are ideal for polarization maintaining fiber amplifiers, fiber lasers, and high speed communication system and instrumentation applications.

How effective is Polarization Maintaining (PM) Isolator?

Polarization Maintaining Isolator is also known as Fiber Optic Isolator which allows light to travel only in one direction. For any state of polarization, it minimizes the back reflection and back scattering in the reverse direction. It is a two port micro-optic device built with PM panda fiber. Polarization Maintaining Isolator is used widely in amplifier systems, fiber optic systems, and lasers. It prevents unwanted feedback into an optical oscillator and the device operations are dependent on the Faraday’s effect turn.

Polarization Maintaining Isolator
Polarization Maintaining Isolator

Faraday rotator is the main component of the optical isolator. The polarization dependent isolator mainly consists of 3 parts like an input polarizer, a Faraday rotator, and an output polarizer. The output polarizer is known as the analyser. Input polarizer vertically polarizes the light traveling in the forward direction. Using the analyser, the light traveling in the backward direction becomes polarized by 45°. The polarization dependent isolators are mainly used in free space optical systems as the polarization of source is maintained well by the system.

What are the devices in which the isolator is used?

PM isolator is used in communication systems, polarization maintaining fiber-optic amplifier and instrumentation applications. Also, the insulating system is used in CATV Fiberoptic Links, Fiberoptic System Testing and Fiberoptic LAN System.

Here are the best features of polarization maintaining optical isolator –

  • High Extinction Ratio
  • High Return Loss
  • High Isolator
  • Epoxy Free Optical Ratio
  • Low Insertion Loss

The light traveling in the forward direction is split by the input birefringent wedge into a vertical component which is called ordinary ray and a horizontal component is known as extraordinary ray. The rotator rotates both the o-ray and e-ray by 45°. Again the output birefringent wedge combines the two components. On either sides of the isolator, collimators are used and the beam is split & diverged in the isolated direction.

There are now companies who specialize in the manufacturing of the isolators for various applications. Based on the requirement of applications, isolators are manufactured precisely. Also, one can get the isolators online and the common PM Isolators available online are Polarization Maintaining Isolator 1310 & 1480 & 1550nm and Polarization Maintaining Tap Isolator 1310 & 1550nm.