Transceiver 40GBase-LX4 compatible to 40GBase-LR4?

All,

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I just stepped over a BOM with both kinds of optics (Juniper with LX4 and PaloAlto with LR4) and I'm not sure wether they are really compatible.

The LX4 seems like a dual use MM/SM transceive while the LR4 is SM only. Not finding any informations except the wavelength which is the same on both. Is this enough to be compatible?

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Thanks