Optical_Comb_Q A_8-16-2016.docx

Questions & Answers 8/16/2016

1. What is the noise performance of the 1556.21 nm laser? Depending on the frequency/phase noise we would decide on the appropriate bandwidth of our electronics. Is there a spec for the bandwidth?

There is no bandwidth spec given. All such questions on the operation of the comb should be derived from our frequency stability requirement 1E-14/sqrt(sampling time) and 1 E-16 on all time scales greater than 1 millisecond whichever is greatest. However if it helps, you can pass along the datasheet attached. We are using the "Ultra" 1.5 um version and stabilizing it to an independent frequency reference. We may change the laser in the future with improved frequency stability. Also see question 2 below.

2. The statement on the fractional frequency stability is unclear to us.

From the specifications: "fractional frequency stability equivalence will be valid as long as the input stability is larger than 1E-14/sqrt(sampling time) or 1E-16 on all time scales whichever is larger." Does larger refer to the stability or to the number (14/sqrt(sampling time) or 1E-16)?

What is meant here is that the stability should be the worse (larger) of the 1E-14 per square root of sampling time or 1E-16. For example at time equal 100 seconds, 1E-14/sqrt(time) is 1E-15. That is larger than 1E-16, so 1E-15 is the requirement. If time is 1 million seconds, then 1e-14 /sqrt(time) is 1E-17 and now 1E-16 is larger so 1E-16 applies.

Incidentally, this might be hard to achieve. I note that the quote from Menlo only says 5E-13 at 1 second. We might have to give on this requirement some if we can get the vibration immunity, size, and 24/7 operation.

3. Are you only interested in the fractional frequency stability of the RF Signal or does phase and frequency noise also matter?

We are only interested in fractional frequency stability therefore phase and frequency noise need only be good enough to meet that requirement. There are conversion formulas in the public domain.

4. "Accelerations allowed up to 0.5 g integrated RMS": Integrated over which range?

Should say 10 Hz to 10 kHz

5. Would 80 MHz also be acceptable? 100 MHz is possible but means some extra effort that we would do only if necessary.

That's fine. Any frequency between 10 MHz and 300 MHz is acceptable.

6. I would like to clarify the statement "30 dys. ADC". ADC means "after date of contract", correct? This is possible depending on when the order date would be. What calendar date would the comb need to be delivered by?

I'm flexible here, but we need this before the end of the calendar year if at all possible.

7. There is the description of Menlos SmartComb attached. Why is this?

I'm not sure how to answer this one. The SmartComb was the starting point in our market research.

8. Will the purchase be based on this quote or will there be another round with possible refinement of the specs, delivery date and number of systems?

I'm flexible here. I could see softening the requirement on vibration or frequency stability somewhat if it meant the comb was possible vs. not possible with the funds allocated.