Optical assembly with an optical element to suppress a parasitic etalon response

An optical assembly, comprising:

• an etalon;
• an optical cavity between a first reflection surface and a second reflection surface;
• and
• an optical element disposed between the etalon and the optical cavity, wherein:
• the etalon is configured to allow a collimated light beam to propagate from an output surface of the etalon to the optical element,
• the optical element is configured to receive the collimated light beam, to change the collimated light beam to a de-collimated light beam, and to allow the de-collimated light beam to propagate from the optical element to the first reflection surface,
• the optical element includes a lens,
• the optical element is positioned to reduce reflections within the optical cavity, and
• the optical element is positioned to reduce reflections between the optical cavity and the etalon.

An optical assembly, comprising:

• an etalon;
• a monitor photodiode;
• and
• an optical element, wherein:
• the etalon is configured to provide a collimated light beam to the optical element,
• the optical element is configured to change the collimated light beam to a de-collimated light beam, and to provide the de-collimated light beam to the monitor photodiode,
• the optical element includes a lens,
• the optical element is positioned to reduce reflections within the monitor photodiode, and
• the optical element is positioned to reduce reflections between the monitor photodiode and the etalon.