Diode Laser vs. CO2 Laser vs. Fiber Lasers - Complete Guide

When it comes to laser engraving and cutting, choosing the right laser engraving or laser cutting tool is key to getting the best results. The most effective laser tools contain these three laser types: diode lasers, CO2 lasers, or fiber lasers, each with its own strengths and weaknesses. 

At OMTech, we’ve seen each laser in practice. Our experts have put together this guide comparing these three laser engraving types, to help you understand how they work, what materials they can handle, and which one might be the best fit for your projects. Whether you’re a hobbyist or a professional, read up so you can choose between CO2, fiber, and diode lasers for your projects! 

Key Takeaways: Diode vs. CO2 vs. Fiber Lasers

We’ve summarized the major differences between diode, CO2, and fiber lasers in the table below:

For beginners, OMTech offers a 40W CO2 laser machine around £550. Know more details about the machine.

Diode vs. CO2 vs. Fiber Laser: How They Work

Choosing whether to use a diode laser vs. CO2 laser might seem like a hard task, but when you understand how each one works, it becomes easier. Here’s what you need to know about each laser technology. 

How Diode Lasers Work

Diode lasers are compact and efficient devices that use semiconductor materials to create laser light. The process begins when an electric current passes through the diode, causing electrons in the semiconductor to jump from a higher energy level to a lower one. 

This transition releases energy in the form of photons, which is the light we see. These photons bounce between mirrors inside the diode, amplifying the light and creating a focused laser beam. Diode lasers are known for their precision and are often used for engraving delicate or fine details on materials like wood, plastic, and metals. 

How CO2 Lasers Work

CO2 lasers operate on a different principle compared to diode lasers. These lasers use a gas mixture primarily composed of carbon dioxide (CO2), nitrogen, and helium. When an electric current is applied, it excites the nitrogen molecules, which, in turn, transfer energy to the CO2 molecules. 

This energy causes the CO2 molecules to emit light in the infrared spectrum. The light is then directed and focused through mirrors and lenses to produce a powerful and precise laser beam. CO2 lasers, like those available in OMTech’s collection, are widely used for cutting and engraving non-metallic materials such as wood, acrylic, leather, and glass, offering deep cuts and high-speed performance. 

How Fiber Lasers Work

When a light source pumps energy into a fiber, rare-earth elements (such as erbium, ytterbium, or neodymium) doped within the fiber are excited. These elements have specific energy levels that enable them to efficiently absorb and emit light.

As the light source excites the atoms within the fiber, they reach an excited energy state. If another photon with the same energy as the excited atoms passes through the fiber, it can stimulate the excited atom to emit a photon with the same energy and phase.

The fiber is placed within an optical cavity consisting of two mirrors—one highly reflective and the other partially reflective. This cavity helps amplify the light through multiple reflections, creating a coherent laser beam. The partially reflective mirror allows a portion of the amplified light to escape the cavity, forming the laser beam output. This output beam can be directed and focused for various applications such as cutting, welding, or marking.

Advantages and Limitations of Diode, CO2, and Fiber Lasers

Now, let's explore the advantages and disadvantages of the three types of lasers.

Advantages of Diode Lasers

Diode lasers are known for their affordability ($400 to $550 on average) and compact size (around 100 grams with heatsink), making them accessible to everyone. They also consume smaller amounts of power than CO2 lasers, which makes them energy-efficient and cost-effective to operate. 

They’re particularly effective for engraving on materials like wood, plastic, leather, and acrylic. Diode lasers’ precise focus also allows for detailed engravings, making them ideal for intricate designs. 

They often have a longer lifespan (up to 50,000 hours), reducing the need for frequent replacements. These lasers tend to have higher electrical efficiency than CO2 lasers (30 to 50% compared to 10 to 20%). 

Some specially crafted diodes can cut/engrave metals like stainless steel, aluminum, copper, and some plastics and fabrics, making them pretty versatile. 

Limitations of Diode Lasers

Despite their benefits, diode lasers have limitations. They’re less powerful than CO2 lasers, so they’re not really unsuitable for cutting thicker materials or working with very reflective or transparent surfaces. The range of materials they can effectively cut is limited, often restricted to softer substances. 

Also, the engraving speed of diode lasers is slower compared to CO2 lasers, which can have a negative impact on productivity in high-demand settings. Their lower power also results in shallower cuts, which might not be suitable for certain applications. 

Advantages of CO2 Lasers

CO2 lasers are highly versatile, making them ideal for diverse materials, including wood, acrylic, glass, fabric, glass, stone, marble, leather, and more. One of the best features of CO2 lasers is that they can cut through thicker materials with ease, which really opens them up to many more uses than diode lasers. 

They have excellent cutting speeds, up to 1200 mm/s (max speed of OMTech machines currently), and high power output, 30 to 150 W typical for home use, up to 400 W industrial. Plus, these lasers operate relatively quietly and produce smooth edges, reducing the need for extra finishing work. 

Their long lifespan and reliability make them a cost-effective option for both small businesses and industrial applications. 

Limitations of CO2 Lasers

One major drawback of CO2 lasers is their inability to effectively cut or engrave metals without extra equipment or treatments. CO2 lasers also tend to have lower energy efficiency compared to diode lasers, which can end up costing you more over time. 

The initial cost of CO2 laser machines is often higher ($2,000 to $10,000), and they need regular maintenance, including the replacement of CO2 gas tubes. CO2 lasers are typically larger and need more space, which might be a constraint for smaller workshops or home use. 

Advantages of Fiber Lasers

Fiber lasers can be used on a wide variety of metals and hard plastics. Although CO2 lasers can be used on these materials as well, they require a thermal/laser bond spray and multiple passes to achieve the desired results.

Another advantage of fiber lasers is they efficiently deliver energy to the material they are dealing with. This means lower energy costs and a more environmentally friendly production process.

Besides, fiber lasers have a longer lifespan and require less maintenance compared to other types of lasers. This means less downtime and operating costs.

Limitations of Fiber Lasers

While fiber lasers are known for their power and durability, fiber lasers, particularly industrial models, can have a higher upfront cost. Home-use fiber laser markers are affordable, but often have smaller, specialized work areas designed for intricate and powerful applications, limiting their versatility in processing larger materials.

In terms of the materials they can work with, fiber lasers are generally less versatile compared to CO2 lasers. If your projects involve a variety of materials, not just metals, you may find that a combination of CO2 and fiber lasers is necessary to meet your needs.

How to Choose Between CO2 vs. Diode vs. Fiber Lasers

Choosing between diode vs. CO2 vs. fiber lasers depends on your specific needs, including the materials you plan to work with, the level of detail you want, and your budget. 

• Materials: Diode machines are great for engraving on materials like wood, leather, and some plastics. However, they struggle with cutting and engraving on thicker materials. CO2 lasers, on the other hand, can cut and engrave a much broader selection of materials, including glass, acrylic, and thicker woods. Fiber lasers usually work with metals and some hard materials.

• Precision: If you need high detail and precision, especially for intricate designs, CO2 and fiber lasers are generally better. Diode lasers can be precise, but they often don’t match the fine detail that CO2 lasers can achieve. 

• Power and Speed: CO2 lasers typically have higher power output, making them faster and more effective at cutting thicker materials. Diode lasers are usually less powerful, so they might take longer to cut or engrave materials. Fiber lasers come in all sorts of power levels, from the low power (under 100W) used for engraving to the high power (over 1,000W) for cutting. The low-power fiber lasers are usually much faster than CO2 lasers.

• Cost: Diode lasers are usually more affordable, making them a good choice for beginners or hobbyists. CO2 lasers are more expensive but offer more versatility and power, which might be worth the investment for more demanding projects. Low-power fiber lasers are similarly priced to CO2 lasers, but high-power fiber lasers can be significantly more expensive.

• Maintenance: CO2 lasers often need more maintenance due to their more complex design. Diode lasers are generally easier to maintain, which can be an important factor for users looking for a low-maintenance option. Fiber lasers demand lower maintenance compared with CO2 and diode laser.

Diode Laser vs. CO2 Laser and Fiber Laser: Which to Choose

Fiber lasers typically work with a 1064 nm wavelength, while CO2 operates with a higher wavelength (10,600 nm) and diode is lower (800–980 nm). When it comes to usage, fiber lasers are much better for industrial engraving and cutting of metal, hard plastic, and ceramics, and more. They’re a lot more precise and a lot faster than CO2 and diode lasers. However, due to their high performance, they’re much more expensive than CO2 and diode lasers.

Ultimately, CO2 lasers are best for businesses that have a focus on non-metals. Diode lasers are affordable options for hobbyists and beginners. Fiber lasers are the best option for metal engraving and industrial applications. 

Check OMTech high-quality CO2 laser engravers/cutters and fiber laser markers.

Here are the pieces created by OMTech CO2 laser machines.

Here are the pieces created by OMTech Fiber laser markers.

Diode vs. CO2 vs. Fiber Laser | FAQs

Can I Upgrade from a Diode to a CO2 Laser, or Vice Versa?

Upgrading from a diode laser to a CO2 laser, or vice versa, isn’t easy. Each type of laser requires different hardware and power supplies, so you can’t just swap one for the other in the same machine. 

If you’re thinking about switching, it’s usually more practical to purchase a new laser system designed specifically for the type of laser you want to use, CO2 or diode. 

How Do Temperature and Humidity Affect Diode and CO2 Lasers

Temperature and humidity can impact the performance of both diode and CO2 lasers. High temperatures can cause overheating, leading to reduced efficiency or potential damage to the laser components. High humidity can cause condensation, which may affect the laser optics and lead to beam distortion or even equipment failure. 

What’s the Difference Between a Fiber vs. CO2 Laser

The main difference between a fiber and a CO2 laser lies in their material compatibility and the type of light they emit. Fiber lasers, whether in fiber laser cutters or compact fiber laser markers, are generally faster and emit a shorter wavelength, making them more efficient for cutting and engraving metals. 

CO2 lasers, on the other hand, have a longer wavelength and a wider range of materials they can work with. They tend to be better suited to non-metallic materials like wood, acrylic, and glass.