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IEC 25G Directly Modulated Laser Packages

IEC is the International Electrotechnical Commission. This standard was formulated by China, and many people are also concerned about it.

With temperature control, it is mainly divided into two categories, one-way heating type with thermal resistance, and two-way heating/cooling type with TEC.

DML, direct modulation, is different from electro-absorption modulation, MZ modulation, MR modulation and other independent modulation functions, which directly modulate signals on the laser. DFB, VCSEL, FP and other lasers can be directly modulated. This standard refers to the appearance and does not involve the specific type of laser in principle. However, in terms of comprehensive application scenarios, the most common type of DML is the DFB laser.

25G DML is used as TO-can, which is mainly used for 5G wireless base station fronthaul and other types. It is slightly different from the 4x multi-channel 25G DML package in the data center.

The TO distribution of 5 pins gives two definitions. This type is mainly unidirectional heating resistance.

5-pin TO header

5-pin TO Can

With 7 pins and 8 pins, the built-in TEC thermoelectric cooler is used for temperature control. The standard defines several categories and dimensions.

7-pin TO header

7-pin TO Can

8-pin TO header

8-pin TO Can

TO-can is divided into two categories according to the position of the lens. In the standard, it is distinguished by spherical and aspheric lenses, but I think this is not the main point. It is more appropriate to distinguish according to one-way heating or TEC two-way heating and cooling.

One-way heating, no TEC required, small diameter TO tube cap can be used, the solder joint of TOSA and TO is located at the base, so that the lens can protrude.

Ball lens TO Can

Lens embedded type, mainly used for built-in TEC type, the diameter of the TO cap is forced to widen, the TOSA package solder joint needs to be moved to the end of the TO cap, not the base, and the top of the TO cap is soldered, the lens needs to be embedded to avoid being damaged by high temperature The lens is warped from the design, causing focus shift.

Aspherical lens TO Can

There are 5 types of 5pin, 7pin, and 8pin. I have drawn a picture to mark the specific size, you can refer to it.

5-pin header TO 56

5-pin header TO-46

7-PIN header TO-39

7- PIN header TO-5

9-PIN header TO-9

TO-56 TO-60 Ball lens

5-pin header, 7-pin header, 8-pin header

For 5G modules that use TO hermetic packaging, usually use the SFP28 module appearance, LC TOSA optical interface, according to this interface, TOSA appearance and size definition, I made a picture. Pigtails are not made, they are available in the standard, but they are used less.

TO can used in TOSA

5pin, 7pin and 8pin, the dimensions of the flexible board

5-pin header

7-pin header

8-PIN TO header

XINXIN GEM mass product TO caps, TO header. We can also customize TO Cap and TO header according to customers' requirements.

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