AF. Optical Faraday Rotators and Isolators

Optical Faraday isolators and rotators for optical feedback elimination and protection of sensitive and feedback-susceptible devices.

AFR in part number means Faraday rotator (supplied without polarizers), AFI means Faraday isolator (supplied with polarizers), PI means polarization-independent isolator (with polarizers)
- Damage threshold (typical): AFI isolators: 1 J/cm^2 at 10 ns; AFR rotators: 5 J/cm^2 at 10 ns; some isolator models are available in TFP version and 5 J/cm^2 at 10 ns DT, please enquire;
Optical power: TGG rods have higher average power threshold than Glass rods (we recommend using TGG for beams with average power roughly >10 W/cm^2);
- Isolation ratio in case of a rotator shows achievable isolation ratio with the use of properly chosen external polarizers.

Basic models of rotators and isolators are specified below, please enquire for custom specs:

Central wavelength, nm Clear aperture, mm1) Part number Rod material Peak Isolation, dB2) Bandwidth
(at >30 dB), nm
Tpeak, % LxWxH (beam height), mm
1250 nm 5 mm 5AFR-1250C TGG 38 dB ±5 nm 98% 65x71x77 (42)
5AFI-1250C 90% 90x71x77 (42)
1030...1070 nm,
fixed
2 mm 2AFR-1064C TGG 38 dB ±10 nm 98% 50x38x46 (26)
2AFI-1064C 90% 78x38x46 (26)
4 mm 4AFR-1064C 38 dB ±10 nm 98% 52x45x51 (28.5)
4AFI-1064C 90% 85x45x51 (28.5)
6 mm 6AFR-1064C 38 dB ±10 nm 98% 55x48x54 (30)
6AFI-1064C 90% 92x48x54 (30)
8 mm 8AFR-1064C 38 dB ±10 nm 98% 62x59x65 (35.5)
8AFI-1064C 90% 100x59x65 (35.5)
10 mm 10AFR-1064C 38 dB ±10 nm 98% 65x66x72 (39)
10AFI-1064C 90% 110x66x72 (39)
12 mm 12AFR-1064C 38 dB ±10 nm 98% 69x71x77 (41.5)
12AFI-1064C 90% 120x71x77 (41.5)
1030 nm,
broadband
2 to 12 mm (2-12)AFRB-1030C TGG 35 dB 980-1070 nm 98% W, H same as fixed, L+8 mm
(2-12)AFIB-1030C 88%
700...900 nm,
fixed
2 mm 2AFR-800C, G TGG (C) or Glass (G) 38 dB ±10 nm 98% 50x38x46 (26)
2AFI-800C, G 90% 78x38x46 (26)
4 mm 4AFR-800C, G 38 dB ±10 nm 98% 52x45x51 (28.5)
4AFI-800C, G 90% 85x45x51 (28.5)
5 mm 5AFR-800C, G 38 dB ±10 nm 98% 52x48x54 (30)
5AFI-800C, G 90% 88x48x54 (30)
8 mm 8AFR-800C, G 38 dB ±10 nm 98% 62x59x65 (35.5)
8AFI-800C, G 90% 100x59x65 (35.5)
10 mm 10AFR-800C, G 38 dB ±10 nm 98% 65x66x72 (39)
10AFI-800C, G 90% 110x66x72 (39)
12 mm 12AFR-800C, G 38 dB ±10 nm 98% 69x71x77 (41.5)
12AFI-800C, G 90% 120x71x77 (41.5)
15 mm 15AFR-800C, G 38 dB ±10 nm 98% 71x81x84 (46)
15AFI-800C, G 90% 140x81x84 (46)
700-880 nm,
broadband
4 to 12 mm (4-12)AFRB-800C, G TGG (C) or Glass (G) 35 dB ±60 nm 98% W, H same as fixed, L+6 mm
(4-12)AFIB-800C, G 88%
710-880 nm,
tunable
4 to 12 mm (4-12)AFIТ-800C, G TGG (C) or Glass (G) 38 dB ±10 nm (tunable) 88% W, H same as fixed, L+50 mm
633 nm 4 mm 4AFR-633С TGG 38 dB ±10 98% 52x45x51 (28.5)
4AFI-633С 85% 85x45x51 (28.5)
5 mm 5AFR-633G Glass 38 dB ±10 98% 52x48x54 (30)
5AFI-633G 85% 90x48x54 (30)
532 nm 2 mm 2AFR-532С TGG 38 dB ±10 97% 30x38x46 (26)
2AFI-532С 85% 75x38x46 (26)
5 mm 5AFR-532С 38 dB ±10 97% 30x48x54 (30)
5AFI-532С 85% 90x48x54 (30)
8 mm 8AFR-532С 38 dB ±10 97% 42x59x65 (35.5)
8AFI-532С 85% 100x59x65 (35.5)
10 mm 10AFR-532С 38 dB ±10 97% 45x66x72 (39)
10AFI-532С 85% 110x66x72 (39)
400 nm 4 mm 4AFR-400С TGG 38 dB ±5 85% 30x45x51 (28.5)
4AFI-400С 75% 60x45x51 (28.5)
6 mm 6AFR-400С 38 dB ±5 85% 30x48x54 (30)
6AFI-400С 75% 70x48x54 (30)
Polarization-independent isolators:
1064 nm 1.53) mm PI35C4) TGG 35 dB ±5 90% 120x48x52 (28)
1064 nm 1.53) mm PI35C35) TGG 35 dB ±5 90% 80x32x32
1) typical apertures, other apertures are available upon request;
2) >60 dB double-stage optical isolators are available upon request;
3) input beam diameter at 1/e^2;
4) the PI35CF model with fiber-input is available;
5) small package.

A Faraday isolator (FI) is a nonreciprocal optical device which transmits the linearly polarized light in one direction and deflects the backward beam. It usually consists of a Faraday rotator and two polarizers. The Faraday rotator is made of magneto-optical active material which is placed into the permanent magnet system (Nd-Fe-B).

Two types of the magneto-optical active materials are available: Terbium-doped glass, Terbium-Gallium-Garnet (TGG) crystals.

The isolator protects a laser source by attenuating the reflected and backscattered light by several orders of magnitude (10^4 to 10^6). It is also used when some devices have extreme sensitivity to optical feedback which can cause intensity instabilities, frequency pulling and other undesirable effects. A Faraday isolator is also indispensable in CPA (chirped-pulse amplificaiton) laser layouts, where seed oscillator and its pump may get damaged easily by occasional back reflections.

 

-TFP: thin-film polarizer modifications are available for some popular laser wavelengths (like 800, 1030, 1064 nm) having higher laser-induced damage threshold of 5 J/cm^2 at 10 ns;

-60dB: double-crystal (two-stage, double stage) optical Faraday isolator units with up to 60 dB isolation ratio are available on custom basis;

-HT: some of the isolator models may be modified to have transmission as high as 92% with a swap of one of the Glan prism polarizers for a Rochon prism, however, this also brings the angle of the rejected beam closer to the main beam path.

- Available wavelength range for customized models: 400 nm to 1250 nm.

AFR in part number means Faraday rotator (supplied without polarizers), AFI means Faraday isolator (supplied with polarizers), PI means polarization-independent isolator (with polarizers)
- Damage threshold (typical): AFI isolators: 1 J/cm^2 at 10 ns; AFR rotators: 5 J/cm^2 at 10 ns; some isolator models are available in TFP version and 5 J/cm^2 at 10 ns DT, please enquire;
Optical power: TGG rods have higher average power threshold than Glass rods (we recommend using TGG for beams with average power roughly >10 W/cm^2);
- Isolation ratio in case of a rotator shows achievable isolation ratio with the use of properly chosen external polarizers.

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