1. Mid-IR Er:ZBLAN fiber laser
There is a need for high power lasers that operate in the 3.0 micron range, especially for medical applications. We have obtained 40 mW of output power at 2.7 microns in an Erbium doped fluoride fiber laser. Pump sources include a 980 nm diode and a high power (~10 W) 790 nm laser diode array.
Future Work:
- Optimize the laser output power by taking advantage of the excited state
absorption (ESA) of the lower lasing level.
- Incorporate double-clad geometry to improve the coupling efficiency of
the pump light into the fiber.
- Develop computer models of the laser rate equations for the various laser
levels to enable us to determine the optimum dopant concentration
2. Upconversion blue fiber lasers
Compact blue laser sources are needed for a large variety of military and commercial applications. Upconversion Tm:ZBLAN and Pr/Yb:ZBLAN fiber lasers are promising candidates of infrared pumpable sources of blue radiation at moderate power levels (~50-200 mW). Preliminary work in our group using a novel laser pump source has produced 22 mW of laser output power at 480 nm.
Future Work:
- We anticipate output powers of over 200 mW
by optimization of the gain parameters.
- Investigate some important effects in these upconversion lasers such as
photodarkening and photobleaching.
- Use high power laser diodes as direct pump sources.
3. High bandwidth SBN electroptic modulators
SBN (Strontium Barium Niobate) is a promising material for modulators because of the high electrooptic coefficient as compared to other materials. One of the goals is to fabricate an SBN modulator with greater that 1 GHz bandwidth that operates at 1550 nm. These modulators have applications in optical computing and communication networks as well as electro-optic interferometers for sensing applications.
4. WDM (Wavelength Division Multiplexing) systems
Multiwavelength sources are needed for WDM communication systems. We are looking into novel multiwavelength source designs and will be investigating the major issues involved in WDM communications such as gain flattening, crosstalk between teh various channels and transient gain saturation.
Research on the electro-optic effect in thermally poled fused silica has been pioneered here at CHTM. This work is relevant because of the use of fused silica fibers in telecommunications and other applications. We plan to construct several devices that can ultimately be incorporated in WDM systems viz. all-fiber switches, amplitude modulators, add-drop multiplexers, etc. This promising technology is in the rudimentary stages of development with huge potential for commercialization, and is an attractive research topic in terms of basic physics and advanced device engineering issues.
5. Chemical Sensors
We are demonstrating the principles and methods that will enable the development of integrated, photonics-based, spectroscopinc chemical sensors that are capable of the reagentless monitoring of trace chemical species in complex environments. We plan to use a technique known as phase fluorimetry in which the measurements are not plagued by intensity variations, a fundamental problem with intensity-based schemes.
6. Ultrafast Lasers
We plan to develop mode-locked Ti:Sapphire and fiber lasers.
These lasers will be used to investigate carrier dynamics in
semiconductor devices. Other applications will include sub-picosecond
spectroscopy and time division multiplexing (TDM).
