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DFB Lasers and Modules
Distributed feedback lasers (DFB lasers) simultaneously provide smooth, tunable control of wavelength and the extremely narrow spectral width required for precise fiber optic communication and spectroscopy applications. Integrated modules provide further narrowing of the spectral line in a compact OEM package that features simple tuning interface. G&H offers a broad range of DFB lasers in the C-band and L-band on 50 or 100 GHz channel spacing as well as at 1310 nm, 1064 nm, and custom wavelengths. Power level options include 40-100 mW out of the fiber for high power 14-pin lasers and 10-18 mW options for high bandwidth 7-pin configurations.
DFB lasers are known for being both single longitude mode and single frequency mode. A DFB laser uses a grating on the chip level structure within the cavity to provide wavelength control. By changing the temperature of the chip/grating, the emission wavelength can be controlled to precise levels and tuned at a rate of ~0.1 nm/°C. Additional feedback or external locking methods can enable extremely stable wavelength control through many years of use.
G&H have developed a number of DFB laser designs to enhance performance for specific customer applications, and new DFB laser designs to increase efficiency, isolation, and accuracy continue to be developed:
- Integrated thermoelectric coolers (TECs) can reduce the overall current consumption or widen the range of allowable environmental temperatures.
- Precision thermistors provide more accurate feedback and control of the temperature at the most critical location, semiconductor chip.
- Internal isolators protect the laser from noise perturbations and catastrophic damage from light returning from other components.
DFB lasers in 14-pin or 7-pin package
DFB lasers provide precise single-frequency and single-spatial-mode performance with smooth tuning capability via temperature or current (chirp) tuning. We offer a range of products with high power and high bandwidth options in a rugged, single-emitter, fiber coupled 14-pin or 7-pin butterfly package. Our high power series offers options up to 100 mW with >2.5 GHz direct modulation speeds, while our high bandwidth series offers up to 18 mW with >12 GHz direct modulation speeds.
In addition to the variety of standard wavelength options in the 1-1.62 mm region, additional custom options are available upon request.
DFB laser modules
Building upon our proven 14-pin packaged DFB lasers, G&H also offers compact OEM modules with excellent linewidth performance. All G&H modules comprise an integrated DFB laser, low noise diode driver, and TEC controller. To operate, the user need only provide a simple 5V power supply and voltage based tuning signals for temperature or current (chirp) adjustment, if required. The incorporation of an ultra-low noise current source for the diode offers a vastly improved linewidth.
The EM650 typically provides linewidth in the range of 100-350 kHz in a hand-sized package, roughly 66x64 mm (2.5”x2.5”) in size. The EM750 features an additional external cavity in a slightly larger package (3”x5”) to reduce the linewidth to approximately 10 kHz while emitting up to 50 mW out of the fiber.
The expanded high bandwidth series of integrated modules includes two compact, easy to use models with direct modulation speeds in excess of 12 GHz. The EM655 offers the lowest linewidth at 1 MHz. The EM657 features an integrated internal switching power supply to remove the inherent voltage potential on the RF connector that is typically associated with laser diodes. The tuning port capacitive load on the EM657 is also lower, allowing for easier control via digital to analog converters.
Applications of DFB Lasers and Modules
Distributed temperature sensing (DTS), fiber optic communications, gas sensing, interferometry, laser Doppler vibrometry (LDV), LIDAR, RF over fiber, seed lasers, spectroscopy.
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