Heat conducting member, optical module, heat sink, and method for preparing heat conducting member

An optical network device comprising an optical module, a heat conducting layer and a heat sink, wherein the heat conducting layer is disposed on an upper surface of a housing of the optical module and is in direct contact with a lower surface of a base plate of the heat sink, wherein:

• the heat conducting layer comprises a transition layer and a protective layer;
• the transition layer is disposed on the upper surface of the housing;
• the protective layer is disposed on a surface of the transition layer that is away from the heat conducting layer;
• a surface roughness of the protective layer is less than or equal to 0.4 μm Ra;
• a material of the transition layer is any one of nickel, chromium, or chromium nitride;
• and
• a material of the protective layer is any one of diamond, diamond-like carbon, or amorphous alloy.