1.05 PWS N6228525RC00P2T Frequency Comb.pdf

Performance Work Statement Frequency Comb with Extensions at 1315 nm, 915 nm, 846 nm and 862 nm

(“Quattro Comb”) Clock Development Division, Precise Time Department

U. S. Naval Observatory

BACKGROUND

The United States Naval Observatory (USNO) is the authoritative source of time for the Department of Defense. For this purpose the USNO’s Precise Time Department maintains an ensemble of high-performing atomic clocks that is used to generate precise time. Because of the lack of commercial vendors for the highest performing clocks, stocking the clock ensemble with systems based on cutting-edge technology requires that these systems be designed and built in-house.

Within the Precise Time Department, the Clock Development Division is investigating atomic clock technology using optical spectroscopy on an atomic beam of calcium. The calcium clock transition corresponds to a wavelength of 657 nanometers (nm), atomic ground state detection utilizes a transition at 423 nm, excited state detection utilizes a 431-nm transition, and there is a candidate 2-photon clock transition at 915 nm that may have benefits over the traditional 657 nm transition. We generate 657 nm spectroscopic light by frequency doubling a 1315 nm laser, since 1315 nm laser technology is further developed than that at 657 nm. Similarly, we use 846 nm and 862 nm sources to generate the detection laser light via frequency doubling.

We require a frequency-comb system that will lock to a narrow 1544 nm laser and transfer the stability to clock lasers at 1315 nm and 915 nm, and to detection lasers at 846 nm and 862 nm, as well as transferring the stability to radio-frequency (RF) signals of 100 mega-Hertz (MHz) and 10 MHz.

REQUIREMENTS

The USNO seeks to procure a frequency-comb system with the following specifications:

Turn-key, robust, fiber frequency comb centered near 1560 nm that automatically mode-locks and remains mode locked indefinitely in a well regulated environment. Repetition rate of 200 MHz. Supports fractional frequency stability below 10-15 at 1 second (s). The mode-locked laser must be rack-mounted, taking up 2RU (rack units) or less space.

Input, beat-detection unit (BDU) and all locking electronics to stabilize frequency comb repetition rate to external, user-supplied narrow (approximately 1 Hz linewidth) 1544 nm laser. Faithful transfer of frequency stability of 1544 nm laser to frequency comb and divided down RF outputs.

Microwave/RF generation, providing signal outputs of 10 MHz and 100 MHz. The frequency stability of the 100 MHz output must be better than 10-14 at 1 s and the stability of the 10 MHz output must be better than 210-14 at 1 s, and the power levels >7 dBm.

The system must include frequency-comb extensions at 1315 nm and 915 nm, with inputs for external user-supplied lasers at these wavelengths and high-SNR balanced BDUs for generating locking signals with less than 100 microWatts (W) of external laser power.

The system must support long-term frequency stability and linewidth narrowing to on order of 1 Hz for these external lasers.

System must include all locking electronics to stabilize external (user-supplied) 1315 nm and 915 nm lasers to frequency comb (itself stabilized to narrow 1544 nm laser) and achieve on order of 1 Hz linewidths.

The system must include frequency-comb extensions at 846 nm and 862 nm, with inputs for external user-supplied lasers at these wavelengths and high-SNR balanced BDUs for generating locking signals with less than 100 microWatts (W) of external laser power.

The system must support long-term frequency stability and linewidth narrowing to below 100 Hz for these external lasers.

System must include all locking electronics to stabilize external (user-supplied) 862 nm and 846 nm lasers to frequency comb (itself stabilized to narrow 1544 nm laser) and achieve linewidths below 100 Hz.

All control electronics and all components necessary to make the lasers operational as “turn-key” systems must be included.

FACILITIES, EQUIPMENT, AND TRAVEL:

Planning and support for the completion of these tasks will be coordinated with the technical POCs listed below for the USNO. No travel is anticipated for this order.

PERIOD OF PERFORMANCE:

The period of performance is nine (9) months or sooner for the delivery of components from award date.

Delivery Address: 3450 MASSACHUSETTS AVENUE NW

WASHINGTON, D.C 20392-5420