Fiber Optic Depolarizers
Phoenix Photonics offers a full range of passive depolarizers to provide pseudo- random polarization output from a highly polarized input.
Passive The Phoenix depolarizers are completely passive, requiring no electrical power.
Principle of Operation The principle of operation is similar to the Lyot type depolarizers based on introducing differential time delays between different states of polarization (SOP). Two orthogonal polarization states are split and transit different optical paths to the output where they are recombined. The differential time delay required is dictated by the source linewidth and structure.
Polarization sensitivity Two categories of depolarizer are available;
- Polarization sensitive in which the input polarization is linear along the axis of a PM fiber. For example, many DFB laser outputs or in sensing applications utilising PM fiber. This class is uni-directional.
- Arbitrary input SOP, generally from a single mode fiber (SMF) where the input polarization is unknown and/or varying with time. These devices are bi-directional.
For both categories, the output fiber is SMF by default, although PM can be selected if required.
Depolarizer type and specification The design of the depolarizer depends on the linewidth of the signal to be depolarized and this is reflected in the price and insertion loss of the design. At Phoenix, we design the depolarizer to be application specific. The standard specified degree of polarization (DOP) is 5%, although better specifications of 1% are available from the superior range.
The in-house flexible design approach enables Phoenix to supply custom depolarizers with a linewidth range that covers over 7 decades of linewidth, from 200kHz to >100nm.
Product overview
Polarization sensitive Arbitrary input SOP
Type
Minimum Linewidth
Insertion Loss (dB)
Broadband (BB)
0.05nm
<1.0 (premium <0.5)
Medium (MB)
1MHz
<1.5
Narrow (NB)
200 kHz
<3.0 (premium <2.0)
Type
Minimum Linewidth
Insertion Loss (dB)
Broadband (BB)
0.1nm
<1.0 (premium <0.5)
Medium (MB)
4MHz
<2.0
Narrow (NB)
400 kHz
<4.5
Datasheets
Technical briefs Broadband - Linewidths 0.1 to 100nm
Depolarizers
Broadband Superior
Miniature Package fixed 10m Coherence Length
Narrowband >200KHz linewidth
| Miniature | Narrowband | Narrowband |
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