Optical crosstalk mitigation for a detector array in an optical receiver

A photodetector device, comprising:

• a photodetector array comprising an array of photodetectors and a plurality of metal structures arranged between photodetectors of the array of photodetectors, wherein the plurality of metal structures are arranged in a first pattern;
• and
• a transparent substrate comprising a plurality of trenches being patterned according to a second pattern that matches the first pattern and at least partially filled with an antireflective material such that the antireflective material takes on the second pattern,
• wherein the transparent substrate and the photodetector array are coupled together such that the first pattern is aligned with the second pattern and the antireflective material covers the plurality of metal structures,
• the photodetector device further comprising:
• at least one air gap formed between the antireflective material and each of the plurality of metal structures.

A method of manufacturing a photodetector device, the method comprising:

• providing a photodetector array comprising an array of photodetectors and a plurality of metal structures arranged between photodetectors of the array of photodetectors, wherein the plurality of metal structures are arranged in a first pattern;
• forming a plurality of trenches in a transparent substrate, the plurality of trenches being patterned according to a second pattern that matches the first pattern;
• at least partially filing the plurality of trenches with an antireflective material such that the antireflective material takes on the second pattern;
• aligning the transparent substrate over the photodetector array such that the first pattern is aligned with the second pattern;
• and
• coupling the transparent substrate to the photodetector array such that the antireflective material covers the plurality of metal structures.