II-VI Marlow Blog

Thermoelectric Applications in Telecommunications

Although II-VI Marlow’s products were originally focused on supplying for defense and aerospace, the corporation has evolved, optimizing the use of thermoelectric technologies in a wider range of industries. The telecommunications industry is a demanding market that can prosper off of the reliability and innovation of thermoelectric applications.

Transmission Lasers (DWDM)

Transmission lasers allow us to have conveniences, such as the radio or ATMs, available for us every day. Could you imagine finishing a delicious meal only to find out that you are in a cash-only restaurant? Even worse, imagine not having an ATM around the corner. The archaic days of having to go to a bank or other source for cash are long behind thanks to transmission lasers. The use of transmission lasers throughout telecommunications is what allows for digital information to transfer over fiber optic cables.

How It Works

Thermoelectric coolers are used to temperature-stabilize semiconductor laser diodes. Laser diodes allow the transition of digital information over fiber optic cables. In Dense Wavelength Division Multiplexed (DWDM), a single fiber optic cable consists of different wavelengths that are unable to drift on top of each other from changes in temperature. Thermoelectric coolers function to either heat or cool the transmission lasers, thus stabilizing their temperature and preventing any wavelength drift.

Pump Lasers (EDFA)

The 980nm pump laser is a common laser diode found in telecommunications. This laser acts as a source of light energy that excites the atoms inside Erbium Doped Fiber Amplifiers (EDFA). Pump lasers overheat when they are not in use, decreasing their lifespan. II-VI Marlow’s thermoelectric coolers remove the heat from the laser which reduces the laser’s temperature and dramatically increases the lifetime of the pump lasers. These pump lasers are used in active optics and originally assisted optical amplifiers to master the long distance communication market.

Photonic Integrated Circuits (PIC)

Photonic Integrated Circuits (PIC) have been applied in telecommunication fields, such as biomedical imaging or optimal commuting. The future of PIC is predicted to be in driverless cars. Light Imaging, Detection and Radar (LIDAR) is a manufacturing area for PICs which ties in with precision imaging and will work to help reduce collisions with driverless cars. So, how does this apply to thermoelectric applications?

How It Works

PICs are built on a collective Si or InP platform. Thermoelectric coolers stabilize the temperatures of PICs, ensuring higher efficiency and a longer lifespan. The main functions of PICs include multiplexing several digital light streams, laser transmissions of the multiplexed signals, light stream detection and de-multiplexing of incoming signals, optical channel monitoring and more. 

Avalanche Photodiodes (APD)

Have you ever been hesitant to invest in a certain application due to doubts in how reliable the new product will be? Avalanche Photodiodes (APD) are exactly what you need in order to alleviate any of those pre-purchase doubts. When a circuit or application begins to exceed in the fixed amount of voltage, the APD works to reverse the process and avoid overproduction. APDs being reverse biased at a high voltage will allow your application to work more smoothly and consistently. 

How It Works

Because APDs are reverse biased at a high voltage, they are likely to create excessive noise created by thermal energy. The telecommunications market uses TECs to temperature stabilize the APDs. TECs can cool down the APD and minimize thermal noise, therefore increasing the APD signal-to-noise ratio and its ability to differentiate weak incoming light pulses. 

CATV Lasers

Watching television has been a normal activity within households around the world for decades. Television is a news, education and entertainment source that contributes to people’s daily lives and without CATV cables many would have to go back to relying on the radio, newspaper or postal office as a way to receive news updates. So, how do CATV lasers tie in with thermoelectric technology?

How It Works

Cable television (CATV) lasers are carried by fiber optic cables that transmit information or radio frequencies that deliver television programming. In CATV systems, a change in temperature can cause different wavelengths on the same fiber optic cable to drift on top of each other. TECs can either heat or cool the CATV lasers to stabilize the temperature and avoid any wavelength drift.

Optical Channel Monitors

Optical Channel Monitors (OCM) are used to measure data on transmission signals, such as optical power and wavelength, in DWDM system node. The thermoelectric coolers temperature stabilizes the OCM, which allows the application to use its tunable light fixture across a broad range of external temperatures.


II-VI Marlow is in partnership with multiple tier-one optical component suppliers. We provide superior telecommunications applications at an offshore price point. The reliability of II-VI Marlow's thermoelectric technologies will allow applications to evolve and succeed in the telecommunications industry.

All of II-VI Marlow’s thermoelectric coolers (TECs) must accommodate the laser’s lifetime and durability in build and design in order to function properly.

Do you have a thermoelectric challenge or question? Feel free to reach out to our experts via the link below. 

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