SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  N07-036 (Navy)
Title:  Modulated Pulsed Laser Sources for Imaging Lidars
Research & Technical Areas:  Air Platform, Sensors, Battlespace

Acquisition Program:  PMA-264 ACAT IV
 RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is “ITAR Restricted”. The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the “Permanent Resident Card”, or are designated as “Protected Individuals” as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected.
  Objective:  Develop high-frequency modulated pulsed laser sources that can improve target recognition and identification capabilities in turbid media.
  Description:  As ongoing research in underwater lidar progresses, it has been proposed that high-frequency modulated pulsed laser sources will improve target recognition and identification capabilities in turbid media. In order to investigate potential gains in this area, modulated pulsed blue-green (400 - 550 nm) laser sources must be developed. The requirement is for high energy (1 - 100 mJ) low repetition rate (0.1 - 10 KHz), and low energy (0.01 - 1 mJ) high repetition (10 - 500 KHz). The pulse widths should be from 10 - 30 ns with very little pulse-to-pulse variation (less than 5 percent or best effort). Furthermore, each of the pulses should envelop a tunable high-frequency (0.5 - 2 GHz) modulation that can be phase locked to an external source with very low jitter. The resultant source must be small, compact, low weight, and ruggedized for use in the field.

  PHASE I: Determine the feasibility of developing laser sources that meet the required specifications and then perform preliminary bench-top tests to explore potential designs.
  PHASE II: Demonstrate a working bench-top system and then develop and test a fully functioning prototype to ensure stability.

  PHASE III: Ruggedize the protype and package it for use in the field. PRIVATE SECTOR COMMERCIAL POTENTIAL/

  DUAL-USE APPLICATIONS: Commercial applications that would benefit from these modulated sources include biomedical optical imaging and imaging through clouds, smoke and flame.

  References:  1. L. Mullen, V. M. Contarino, and P. R. Herczfeld, “Hybrid Lidar-Radar Ocean Experiment,” IEEE Transactions on Microwave Theory and Techniques, Vol. 44, no. 12, December, 1996, pp. 2703-2710. 2. L. Morvan, N. Lai, D. Dolfi, J. Huignard, M. Brunel, F. Bretenaker, and A. Le Floch, "Building Blocks for a Two-Frequency Laser Lidar-Radar: A Preliminary Study ," Appl. Opt. 41, 5702-5712, 2002. 3. D. Kao, T. Kane, and L. Mullen, "Development Of An Amplitude-Modulated Nd:YAG Pulsed Laser With Modulation Frequency Tunability up to 60 GHz by Dual Seed Injection," Opt. Lett. 29, 1203-1205, 2004. 4. L. Mullen, V. M. Contarino, and P. R. Herczfeld, Modulated Lidar System (U. S. Patent No. 5,822,047, 13 October, 1998.)

Keywords:  Laser; Modulation; Pulse; Image; Contrast; Communication

Additional Information, Corrections, References, etc:
SBIR N07-036 Detailed Specs.pdf
SBIR N07-036 Detailed Specs.pdf

Questions and Answers:
Q: 1. Is there a hard upper bound on the modulation frequency? Could it be 50GHz for instance?
A: The upper bound is limited by available hardware to 10GHz for the underwater applications. Specifically, the limitation is on the receiver side - detectors that have a bandwidth of 50GHz have very small apertures and/or no gain, which isn't optimal for low light level applications. If there was a way of reaching 50GHz modulation rates while still having the ability to be tuned to lower frequencies, that would be useful for exploring future higher speed applications.
Q: Does the pulse envelope have to be Gaussian? Can it be a square pulse envelope?
A: No, the pulse envelope does not have to be Gaussian. A square pulse envelope is acceptable. There are no requirements for the shape of the pulse envelope.
Q: 1. Is there a hard upper bound on the modulation frequency? Could it be 50GHz for instance?
A: The upper bound is limited by available hardware to 10GHz for the underwater applications. Specifically, the limitation is on the receiver side - detectors that have a bandwidth of 50GHz have very small apertures and/or no gain, which isn't optimal for low light level applications. If there was a way of reaching 50GHz modulation rates while still having the ability to be tuned to lower frequencies, that would be useful for exploring future higher speed applications.
Q: What is the required linewidth for this laser?
A: There is no specific line width requirement. If you need a number to work with, 0.01nm or less would be more than adequate. But if it were two or three times this, that would not necessarily be a problem. However 0.1nm will probably be too big, so definitely keep it less than that.
Q: Must the required laser source operate in both pulse regimes (high pulse energy/low PRF and low pulse energy/high PRF) simultaneously or simply in one of the two regimes?
A: No. The high pulse energy/low PRF is for the blue system at 486nm and the low pulse energy/high PRF is for the green system at 532nm. Pick whichever one is more compatible with your company's capabilities. If you can do both in one system, that would be fantastic, but it is not required.
Q: What is the required linewidth for this laser?
A: There is no specific line width requirement. If you need a number to work with, 0.01nm or less would be more than adequate. But if it were two or three times this, that would not necessarily be a problem. However 0.1nm will probably be too big, so definitely keep it less than that.
Q: Must the required laser source operate in both pulse regimes (high pulse energy/low PRF and low pulse energy/high PRF) simultaneously or simply in one of the two regimes?
A: No. The high pulse energy/low PRF is for the blue system at 486nm and the low pulse energy/high PRF is for the green system at 532nm. Pick whichever one is more compatible with your company's capabilities. If you can do both in one system, that would be fantastic, but it is not required.
Q: Does the pulse envelope have to be Gaussian? Can it be a square pulse envelope?
A: No, the pulse envelope does not have to be Gaussian. A square pulse envelope is acceptable. There are no requirements for the shape of the pulse envelope.

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