Telecom Band Geometric Amplifier

TECHNICAL POINT OF CONTACT (TPOC)
Ali Sayir
PROJECTED CMMC LEVEL REQUIREMENT
Level 1
TECHNOLOGY AREAS
None
MODERNIZATION PRIORITIES
FutureG
|
Quantum Science
KEYWORDS
Telecom Laser, Optical Amplification, Geometric Amplifier, Berry Phase
OBJECTIVE
The primary goal of this initiative is to design, build, and test a device that uses geometric phase (also known as Berry phase) to amplify laser light in the telecom band (wavelength ~ 1,550 nm). The device will use radio-frequency modulation of linear, lossy elements to produce optical amplification that outperforms existing technologies in parameter regimes of interest to DOW
DESCRIPTION
Present-day devices for amplifying telecom laser light mostly produce gain by incoherently pumping a medium (optically or electrically), or by coherently pumping a nonlinear medium with a laser. Both approaches are technologically mature, and offer a range of performance tradeoffs.
In contrast, geometric amplification is a gain mechanism that has only been recently proposed, and to date it has only been demonstrated in the acoustic domain [1]. However, the principle of geometric amplification can be applied to any domain. It can be realized using coupled resonators consisting only of linear, lossy components, so long as they can be modulated at a frequency comparable to the resonators' decay rate [1].
In the telecom domain, this can be accomplished using a pair of fiber loops that include electrically tunable phase shifters that can be modulated at ~ 1 MHz. The adiabatic evolution associated with this relatively slow modulation (together with the components' intrinsic loss) results in the accumulation of a geometric (Berry) phase [2,3] whose complex part can be engineered to provide gain [1,4,5].
Geometric gain differs existing forms of amplification in several respects, including that it achieves photon-number gain through rf modulation. This may offer practical advantages in terms of reduced device complexity, size, and power consumption.
PHASE I
Produce a complete design for a prototype telecom-band geometric amplifier based entirely on commercial off-the-shelf components. The design should be based on quantitative simulations that incorporate the components' specifications into the mathematical model of geometric amplification.
PHASE II
Construct the device and optimize it with respect to the following performance metrics: gain, bandwidth, power consumption, added noise, and harmonic distortion. The device should exhibit > 10 dB gain with bandwidth > 100 kHz.
PHASE III DUAL USE APPLICATIONS
Collaborate with industrial and/or DOD lab partners to incorporate the lessons learned from Phase II into a commercial on-chip geometric amplifier that is superior to existing optical amplifier technologies in parameter regimes of importance to DOD.
REFERENCES
J. R. Lane et al., Complex Berry phase and steady-state geometric amplification in non- Hermitian systems. ArXiv:2503.23197 (2025).
M. V. Berry, Quantal phase factors accompanying adiabatic changes. Proceedings of the Royal Society of London Series A 392, 45 (1984).
B. Simon, Holonomy, the Quantum Adiabatic Theorem, and Berry's Phase. Physical Review Letters 51, 2167 (1984).
J. C. Garrison and E. M. Wright, Complex geometrical phases for dissipative systems., Physics Letters A 128, 177 (1988).
K. Y. Bliokh, The appearance of a geometric-type instability in dynamic systems with adiabatically varying parameters. Journal of Physics A 32, 2551 (1991).